How Sex Works: Why We Look, Smell, Taste, Feel, and Act the Way We Do – A Surprising and Engaging Exploration of Human Sexual Evolution

by Sharon Moalem

“Read this book and discover sex again, but from a scientific perspective, and see why it evolved. It’s almost as much fun, and needs less energy.”
— Peter Macinnis, author of 100 The Greatest Breakthroughs in History " How Sex Works manages to inject science writing with the prurient thrill of a gossip rag."
— O magazine Medical maverick and New York Times bestselling author of Survival of the Sickest Dr. Sharon Moalem presents an insightful and engaging voyage through the surprising history and evolution of sexual reproduction. Fans of Freakonomics, Blink, The Owner’s Manual , and Why Do Men Have Nipples will find many engaging insights in How Sex Works .

Genres: Science, Nonfiction, Sexuality, Psychology, Biology, Health, Evolution

288 pages, Paperback

First published January 1, 2009

About the author

Sharon Moalem, MD, PhD, is an award-winning physician-scientist and geneticist. He is the author of the New York Times bestseller Survival of the Sickest and Inheritance, an Amazon Best Science Book of the Year, among other books. His work brings together evolution, genetics, and medicine to revolutionize how we understand and treat disease, and his clinical research led to the discovery of two new rare genetic conditions, and to his discovery of a first-in-class antibiotic which targets ‘superbug’ infections. His books have been translated into more than 35 languages.

Reviews

[Charlene · Rating 4 out of 5]

Great book about sex. Moalem brings a nice balance to the discussion. Using a lot of traditional ideas about sex (e.g. sperm is plentiful and eggs are rarer) as well as more updated ideas (e.g. human males' large balls serve as refrigerators for sperm that are ready to compete), Moalem wrote the book about sex I have been searching for.

Usually books about sex involve what Gould calls "just so stories" in which evolutionary psych people go to extraordinary lengths to hold onto outdated ideas that serve to promote biological essentialism. If they are not doing that, they promote the idea that everything we have learned thus far is wrong and we are really all cheaters at heart. This book talked about mate choice and monogamy in the most balanced way I have read to date. Through the use of prairie vole studies and research done on the HLA immunity genes (MHC), Moalem examines why some people might be more predisposed to cheat and some less. Not wanting to seems as if he is advocating for cheating, he reminds his reader they have a choice about whether or not to follow their desires. But, he only takes up a very short portion of the book with any type of moralizing.

Here are some of the things I learned or re-thought about while reading this delicious book:
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The deadly sex appeal of queen bees:

The queen bee releases pheromones that bring helpless males to her, compelling them to mate with her in mid-flight, thus donating their sperm. As they ejaculate and fall to their deaths, their penis falls off inside the queen, stuck there like a skull and crossbones warning to other helpless males.

Does the warning work? Hell no! The other males get a whiff of the queen's deadly but delicious scent and go penis diving. They locate and pull out the penis from the previous male, copulate with the queen and leave their own sperm and penis behind, and then they too fall to the ground where they will lay there in post copulatory confusion until they die within hours from dehydration.

Meanwhile, the queen continues flying along, luring more males to her sting chamber.
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The smell of your lover:

Have you ever loved the smell of your lover so much, you couldn't get enough? Was sniffing them like a drug? According to geneticist Sharon Moalem, it's not because they smell objectively good. It's that you are sniffing out their HLA genes (MHC). Your nose helps you find someone with a different HLA than you, so you don't have children with genetic defects, but not so different that they have problems coping in your part of the world. That Goldilocks zone of smell is what is called "chemistry."
People who attracted to each other often say things such as, "You are hot!," or "I don't know what it is about you but you drive me wild." If we put that through the genetic translator, your genes are screaming, 'Hey baby! You have just the right combination of HLA genes for me!"
Unlike looks, there is no universal pleasing smell of another. Moalem suggests, "There is no Brad Pitt of smell."
If you are crazy about the smell of your lover when they get out of the shower (when they have not used scented soap or cologne) then chances are you will have a more satisfying relationship than those who are not attracted to their lover's smell. Those with optimally different HLA genes have better sex, are less likely to cheat, and report happier marriages.
The more alike your HLA genes, the more likely you are to cheat. For example, if you have 50% of your HLA genes in common, you are 50% more likely to cheat than the average person. (I didn't confirm methods and am just relating what I read in a book).

How being on the pill can trick you into being with someone who will eventually feel more like a brother and less like a lover:

A woman's natural olfactory system (smell) helps her pick out someone she has chemistry with. She sniffs out the immune genes of a potential lover. If his immune genes are sufficiently different from hers (but not too different), she will love his smell, be sexually attracted to him, and will be less likely to cheat or leave him.

But, if she is on the pill, her system thinks she is already pregnant. When a woman is pregnant, her olfactory system sniffs out immune genes that are *similar* to her, like family. This will ensure that her genetic relatives will help her care for her baby.

So, if she is on the pill, she is more likely to find a brother type person attractive. When she goes off the pill, depending on how different their HLA genes are, she will no longer feel sexually attracted to him and will instead feel like she is kissing her brother.

Advice from Sharon Moalem and everyone else who has ever studied this, take some time off the pill before you decide to spend your life with someone. If you like the way they smell when they are clean (but not perfumed), chances are you will remain attracted to them.
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The quality of sperm:

There is apparently a way for men to up the quality of their sperm. A superior male trying to create a baby can expect that a whopping 15% of his sperm are normal. The other 85% or more tend to have 2 heads, no tail, or got no game when it comes to swimming. But fear not. According to a new study (haven't had a chance to look at methods), if men look at porn, their brain sends a signal to their sperm production regions to produce a higher percentage of fully formed, ready-to-fertilize, swimmers.

Here is the catch. It can't be girl on girl action. The highest rates of quality sperm production is seen after viewing porn with both females and males.
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The sperm attack!:

Having trouble getting pregnant? This might be because some women's bodies recognize their partner sperm as an attack on the immune system and feel the need to attack back. Thus, the woman's body might work extra hard to get rid of the sperm before it can fertilize the egg.

If a woman wants to lower her body's immune response to her partner's sperm, it is suggested that she engage in frequent oral or anal sex, so that she can ingest the sperm into her body, allowing it to get used to it in little doses so that it will recognize the sperm as "self".

[Hester · Rating 3 out of 5]

This is a well-written, interesting book. If you read science articles frequently, most of what you read is not new. I still ended up learning how female ejaculation is still a mystery to many doctors. Warning: while most of the book is not graphic, a couple passages gave me pause. I learned that while I am not a homophobe, homosexual duck necrophilia really, really grosses me out.

[Arminzerella · Rating 2 out of 5]

How Sex Works takes us on a tour of sex – its biological costs and benefits, its anatomy, why we’re attracted to the people we’re attracted to, homosexuality, and the genetic disorders that result in ambiguously sexed individuals. Reading this was like being allowed to smell your favorite food – there’s just enough to tantalize you, but not enough to satisfy your interest/craving. Dr. Moalem’s narrative is easy to follow and very readable, but he just doesn’t delve into things. A lot of what he presented, too, was information I’d already seen, heard, or read about (although, I have to say that male monkeys paying for porn – looking at images of female monkeys’ hindquarters – by giving up their fruit juice was a new one on me). Since this is totally readable, I’d recommend it if you’re looking for a quick and interesting overview of sex. But if you’re looking for something amazing on a similar topic, you absolutely need to read Mary Roach’s book, Bonk: The Curious Coupling of Science and Sex. It’s fantastic. Her footnotes alone are jam-packed with information to entice and entertain.

[cinderines · Rating 3 out of 5]

ceviri kotuydu:( cok temel bir kitap. daha once konuya dair okuma yapmadiysaniz baslangic olarak secebilirsiniz ama imkaniniz varsa orijinal dilde okumaniz daha mantikli olur bence.

[Jocelyn · Rating 4 out of 5]

Had a friend recommend this who likes nonfiction books that describe how and why different body process work and happen. This broke down what is going on in male and female bodies and in various animals. The most fascinating parts were when animal processes were described and explained and how similar to humans they are (duh we are animals too.) This books discusses more studies and scientists, psychologists, other research professionals than I can count. Basically this book is what an anatomy or medical class would discuss when talking about the two sexes and the evolutionary push for sex.

[D Dyer · Rating 3 out of 5]

This book starts out much more strongly than it finishes. In its earlier chapters, the ones in which the author goes about the business of explaining the mechanics of sexual response, the writing is clear and still extremely relevant though the book was written not quite a decade ago. But both the science which the author explores and the viewpoints the author expresses definitely show their age increasingly as we get further along in the text. Some of the authors references to Queer issues and STI treatment and transmission reflect attitudes that are definitely not current with what is advocated bye most contemporary sex educators and which were to some extent falling out of favor even at the time that the book was published. With that in mind, some of the information on the technical mechanics of sex is great and really well-presented here. This is a book I can advise Reading if you aren’t familiar with the subject but I would also advise making careful use of the authors reference notes, checking his statements against the current science.

[Giselle Odessa · Rating 4 out of 5]

كتاب يتحدث عن الجنس بطريقة علمية, اختلافات جنسية بين الذكر و الانثى, سبب انجذابنا لاشخاص معينين بفترات معينة, و هناك فصول تشرح عن الامراض الجنسية و طرق الوقاية منها.
اي شخص يقرأ كثيراً من المقالات العلمية سيجد كثيراً من المعلومات المألوفة, الكتاب بشكل عام مفيد و ممتع.

[JES · Rating 3 out of 5]

An author can't go wrong, I'd guess, by including the word "sex" in his or her book's title. It helps if said author's bio mentions appearances on CNN and The Daily Show. It helps if some of the blurbs on the cover are by the authors of books whose own titles include The G Spot and The Technology of Orgasm.

Still and all, by the time you finish How Sex Works: Why We Look, Smell, Taste, Feel, and Act the Way We Do, you may be left wondering: what the heck kind of book did I just read?

Consider the chapter titles, which include such as these:

-- Girls Just Want to Have Fun
-- I'm So Excited and I Just Can't Hide It
-- Let It Be
-- Jagged Little Pill
-- Good Vibrations

These pop-culture-driven chapter titles said to me -- especially considering all the sure-fire gimmicks cataloged in the first paragraph of this review -- that the book would romp playfully through its subject matter. I'd probably encounter a lot of sly jokes and puns, and a certain amount of the old Monty-Python wink-wink-nudge-nudge sort of provocation.

Er, well, no.

From the Introduction:

We're here to explore human sexuality from beginning to end – what we like and why we like it; how it makes us feel; how it can go wrong; and how human intervention, through cultural traditions, scientific discovery, or both, can divert nature's path – across history, geography, culture, gender, and orientation... how sex works.

What Dr. Sharon Moalem (yes, he's a doctor: a neurogeneticist (!) and evolutionary biologist) says in that paragraph sounds encouraging. He's going to cover it all, isn't he? In fewer than 300 pages, at that. It's gonna be concentrated. All right, you think.

But then there's the small matter of how he says it. A single 300+-word sentence, multiple independent clauses, and not a whole heck lot of Anglo-Saxonisms. The whole thing fraught with em dashes, semicolons, and even an ellipsis to boot.

And -- I can't help noticing this sort of thing -- this is his opening sentence. The grabber. The sentence that he and his editors sweated over more than any other.

The problem plagues How Sex Works for most of the remainder of the book. Although this is far from an academic treatise of the topic, it's not a book whose contents you might find excerpted in (say) Esquire or Cosmo. Carrie Bradshaw will not be citing it aloud, musingly, in Sex and the City II. So if that's what you're hoping for, keep hoping.

Still, the book's content is interesting -- here and there, very interesting.

The first couple of chapters cover the physiological basics, for women and men, such as how our bodies change with puberty, the mysteries of pubic hair, and breast and penis sizes. (Bet you didn't know how the latter is typically measured, in studies of such things, to ensure consistency. Let's just say the combination of relaxation and stretching sounds positively yogic.) Moalem discusses the hydraulic stuff here, too: fluids (where they come from, where they go, why they go there instead of someplace else), how things fit together (or don't), the basic propulsive mechanics.

For me, the best chapter in the book was the third, "I'm So Excited and I Just Can't Hide It." This chapter deals with the rules of attraction: how our bodies tell us just who, exactly, will turn our heads.

When Mom or our good friends counsel us that opposites attract, they mean psychological and/or emotional opposites. Intellectual types may hang out with intellectuals, but they can't help being diverted by the scatterbrains. Artists lie down with logicians, social butterflies with wallflowers, the strong-willed with the wimps. Yes, that may (or may not) be true in the long run. But what catches our eye in the short?

It might be more accurate to ask, What catches our nose?

Moalem reports on several varieties of what he refers to as "the T-shirt test": studies which neutralize, as much as possible, the effects of odors other than an individual's own, and test the responses of people exposed to the resulting "pure" odor.

The first of these studies asked a group of men to go without using any normal deodorants, aftershave lotions, colognes, or other such products for forty-eight hours. (The researchers gave them odorless soap and aftershave; this wasn't going to be a "B.O. test," after all!) During that time, the men were to wear T-shirts for two nights in a row. Afterward, about the same number of women were asked to rate the attractiveness of each T-shirt.

The result wasn't what might be obvious. Women didn't consistently choose T-shirts which smelled "good" in any conventional way, or even those which simply didn't smell "as bad." Rather (emphasis added):

Time and again, volunteers were more attracted to the smell of shirts worn by men who had immune systems that were somewhat different from their own... especially a group of very important genes that make up a key part of our immune system: human leukocyte antigen system, or HLA.

Got that? What drew the women to one T-shirt or another turned out to be something that most of us didn't even know existed. ("'HLA'? Que?")

Moalem doesn't cite a study of a directly analogous T-shirt test in the opposite direction. Instead, he discusses one in which women (likewise "deodorized") slept in one T-shirt during the most fertile part of their menstrual cycles (days 14-15), and in a different one on days 21-22, when they weren't actively fertile:

Sure enough, when men were asked to sniff the shirts and pick their preference, they picked the smells from the fertile phases again and again... [So] women may be wired to sniff out men who will provide the right traits to give them the healthiest babies. And men in turn may be wired to sniff out women who are ready to make babies.

It's tempting to quote at greater length from Chapter 3, which delves into matters like whether gender preference as well as gender itself determines attractiveness, what babies find attractive in a human face, the role of symmetry in attractiveness, and what goes on between our ears neurochemically when we're shown a picture of someone attractive. (Did you know "what researchers have long known about faces -- when you blend the features of hundreds of random faces, the resulting 'average' face is inevitably beautiful"? I sure didn't.)

But in my view, good though that chapter is, the book loses steam thereafter:

There's another chapter about hydraulics. There's a lot of information about things which can go wrong, either with sex itself or with the reproductive processes resulting from it. X and Y chromosomes, hermaphrodism, sex hormones all take the stage. STDs come in for their share of attention, as does contraception (natural and otherwise).

For me, the problem with these later chapters was that none matched -- probably could match -- the sheer human interest of Chapter 3. (Neither could Chapters 1 and 2, but when I read them I didn't know what was coming next.) The tone and general feel too often trailed off into the dry and clinical, even when the information was (a) very current (as it often was), (b) based on the latest research, and/or (c) unfamiliar to me.

It's hard to care about molecules, lubrication, viruses, and genes when you've just wandered through more than 30 pages with your head in an aromatic cloud, y'know? Maybe those Chapter 3 pages just (ha ha) mysteriously smelled better to me.

But I don't think the answer is that simple, or that mysterious.


[NOTE: This review originally appeared, in slightly different format, at The Book Book.]

[Michelle, the Bookshelf Stalker · Rating 4 out of 5]

I was very surprised by how much information is in this book. The author, Dr. Moalem does not dwell on one topic for long. Because of this, the book kept my interest. Some of the information shocked me (not in a bad way, just I never heard of it), and I was so surprised I looked it up the internet to confirm (or deny) his research.

[Tamiko · Rating 4 out of 5]

Very interesting read. Sex, attraction, monogamy, puberty, etc. are all approached from a purely clinical and research based perspective.

[Patrick · Rating 4 out of 5]

Still don't get it.

[Lana Higbee · Rating 5 out of 5]

Definitely not for the prudish, but also not a prurient book. It's a scientific (though not clinical and boring) discussion of reproduction, sexual identity, and sexual attraction. I found it fascinating.

[Darren-lee · Rating 4 out of 5]

I don't think the title of this book does it justice. It's not a 'how to' book, but a 'science of'. Really interesting actually.

[Nate C. · Rating 5 out of 5]

Excellent book summarizing our current understanding of sexual behavior, reproductive biology, among other things. Different chapters covered female orgasm (and ejaculation), birth control, and the connection between pheromones and the immune system. Although I'd learned many of these facts in previous classes, the author did a good job of both explaining and summarizing the research in an understandable fashion.

[Hayley · Rating 3 out of 5]

I'm a big fan of Sharon Moalem's other books "Survival of the Sickest" and "Inheritance" so I looked forward to reading this but I felt it lacked structure, with random facts popping up all over the place and chapter titles having only a sparing relevance to their contents. It was worth a read.

[C.D. Woods · Rating 4 out of 5]

In one word: “fascinating”.
First of all, this book is not a text book but it could easily serve as a primer to any undergrad: Introduction to Evolutionary Human Sexuality.
Secondly, Dr Moalem is an accomplished MD, PhD, and award winning Neurogenetiscist who harbors an intense passion for his field of study; and this factor shines brilliantly in this creation.
And lastly, my personal opinion is: the author is truly a master of finding the subject’s marrow; stripping the clinical down to its most articulate conveyance and blending the final product into something that is not only understood but made visceral.

This book’s joy lies exactly in my first premise; the fact that it was not written as a text book per-se; its aim does not grapple the details of synthesizing proteins to solve a specific problem nor does it try to isolate and explain elements within a particular conundrum. In short, rather than taking the Pointdexter approach of two colleagues discussing details back and forth, it’s as though we are invited into Dr. Moalem’s private study for a snifter of Brandy and some good ole’-fashioned dialogue; relaxed, inquisitive, and ambitious; we have the privilege of picking his extensive expertise and passion.

The text excels at formulating really good questions and then exercises a holistic framework to derive conclusions. Utilizing scientific research, empirical evidence, logical deduction, and the proverbial what if college try, the book bravely asserts very probable theories which might seem shocking but on some very primal level ring true.
For example, this paraphrased excerpt: “There actually are some pretty universal standards for what humans tend to find visually attractive, and they start with the cliché – tall, dark, and handsome. And there’s a perfectly good reason- they are likely to have healthier sperm. …Folate is critical to the production of new cells. It’s especially important during periods of rapid growth, as in pregnancy. In the average healthy man, up to 4 percent of the sperm in his ejaculate has the wrong number of chromosomes, called Aneuploidy. Men who possess more Folate had as much as 30 percent less Aneuplodidy.
…Ultraviolet rays destroy Folate! Melenocytes in skin absorb ultraviolet radiation and releases it as heat, protecting the body from its harmful effects. So the darker a man is the more likely he is to be protected from ultraviolet damage, which means less Folate is destroyed, which means the healthier his sperm.” Now, Dr. Moalem laboriously connects the details more vigorously than I’ve paraphrased here but maybe this diminutive example highlights the strength I find in this book. It’s not just what’s pointed out; it’s what can be inferred. Looking at the inter-relatedness of stimulus conditions, possible leaps in evolution, and examining nature’s seemingly grand purposefulness, many eureka moments were brought into focus. I found myself formulating curious connections that I although not great leaps of faith or reasoning, the seemingly unknowable void just crystallized. And no matter how you slice the bread… That’s just plain fun!

As mentioned earlier, this book is not a text book –per se. Although the text crosses lanes into many fascinating science territories; from why humans have a very strong disposition towards infidelity to where and what factors might involve homosexuality’s survival throughout human history. No single fact is extrapolated from its origin through its current condition. Entire volumes have been scribbled on chromosomal aberrations in Down’s syndrome inheritors alone. However, this book sets fire to the imagination and provides many starting points for curious; and thus, outlines various pathways for personal research. Hence, in my opinion, How Sex Works: Why We Look, Smell, Taste, Feel, and Act the Way We Do serves as a fantastic jump point. There are many discoveries that might make the reader gawk. However, there are also plenty of verifiable references supporting his claims.

Overall, if you can’t tell… I believe this read is definitely worth your effort. : )

[AnnaMay · Rating 4 out of 5]

Okay, so I thought: should I post this title or shouldn't I?

I liked this book! I tend to be medically/scientifically-minded in my approach to things, so when I read this title, I knew it would be up my alley. Yes, the first chapter was a drag as he leaned heavily on evolution, but after I put that into context in my mind, I found his medical explanations for things very enlightening. I liked how he was tasteful in his commentary (Moalem has is PhD in something or other to do with the topic...I can't quite remember.)

One tidbit example of something I learned: you know how a person is attracted to the smell of another person? Well, when a woman goes on the pill, it actually alters that attraction to be opposite of what it would naturally be, so she'd be repelled by the smell of her mate and attracted by the smell that would usually repel her. Interesting, eh?

Let's see, what else was fascinating? One personal conclusion: a lot more is going on with sexual attraction and relationships than we realize or understand yet. I've lost the need to judge others and feel a more empathetic response when confronted with sexual behaviors in others that differ from my preferences. I think, due to the fall, genetic things are going on that we aren't prepared to explain and my response of empathy and being able to put it into context of the fall of Adam helps me feel at peace and not so distraught with sexual trends today. I feel very very comfortable claiming that I can't judge and I don't know all of the circumstances.

Another tidbit: Did you know that the eggs my daughters came from were actually formed in-utero in my mother? Whoa....mind-boggling, eh? Yep, because I was formed in my mother's uterus and as an embryo, I was prepared with my complete set of eggs before I was born. That means the eggs my two daughters came from existed when I was an embryo within my mother. :) Cool thought, eh?

[Dora · Rating 3 out of 5]

I won this in a "First Reads" giveaway, and am so excited to dig into it soon!

So I finished this and I really enjoyed reading it! It definitely gave me quite a bit of food for thought.

Many topics related to human sexual activity and reproduction were covered here, and at times it felt unfocused. I think the biggest underlying theme related back to the evolutionary purpose of everything we do sexually, but that covered quite a bit of territory! I might have preferred this book if it were more narrow in its scope and therefore deeper with more case histories and specific examples. Then again, that would have been a different book entirely. For what it was-- a broad overview of human sexuality from an evolutionary biology perspective-- it was pretty good!

If evolutionary biology/natural selection is the overall point of the book, I'm not sure that this book completely convinced me of the "nature" side vs "nurture". The author cites many studies to demonstrate that certain proclivities are deeply ingrained in our genetics but at times I felt he didn't prove causation. For example, halfway through the book he discusses the evidence that gay men are highly likely to have gay male siblings (and other relatives). To me, this alone does not say there is a genetic relationship to homosexuality. What if men are just more likely to come out of the closet when their family has already gone through "coming out"? If they are more open minded about any homosexual feelings they have because their cool older sibling is a positive example?

In any case this book was great because it got me thinking about all these things; I found myself challenging the author in my head and also wanting to read more about the studies he cites.

[Megan Jones · Rating 3 out of 5]

This book was somewhat informative. It would have helped greatly to have diagrams to accompany some of the descriptions. As a woman trying to better understand my body on a scientific level, I would have loved to have something to look at while reading that could show me exactly where the parts he was discussing were located. After reading Sex at Dawn: The Prehistoric Origins of Modern Sexuality , I would say these two book pair nicely together. Sex at Dawn: The Prehistoric Origins of Modern Sexuality tends to look more into the evolution of humanity, and shed more interesting facts based on history while How Sex Works: Why We Look, Smell, Taste, Feel, and Act the Way We Do gives more biological explanations for the way our bodies function the way they do. I would definitely recommend this book to anyone interested in better understanding their own body. While some of this was tedious and dry, I did enjoy learning new things about my own body, especially details about the Pill, and our olfactory senses. Also loved that it was a pretty quick read!

[Jay · Rating 4 out of 5]

Who knew I was doing so many things wrong???

No, actually this isn't quite that sort of book. It's a scientific discussion of many different things related to sex, including the dispelling of many myths that I have heard (and sometimes believed) through my life. While much of the information was not entirely new to me, there were definitely things I had not known before, and even for the things that I did feel I knew, the confirmation of my information was nice. And I only occasionaly felt squeamish.

The information about how evolution shaped some of the things we do (which is what I felt the "Why we Look, Smell, Feel, and Act the Way We Do" subtitle promised me) was the most interesting part. Even in cookbooks, "Why?" is my favorite question, and this book did a lot to explain the whys of sex. If that's the sort of curiousity you are blessed/cursed with, then you will enjoy this book, despite the lack of jokes in the text. The chapter on homosexuality was especially interesting to me; I didn't realize how common homosexuality is in the animal kingdom and especially in primates, or how evolution would favor homosexuality. The chapter on STDs was the scariest... you might want to read that chapter during daylight hours.

Now when I find myself in the sort of conversations that I never find myself in, I now have a lot more information to share. Or if there's a "sex myths" category in a trivia night, you'll want me on your team. And if I had to choose a topic to be extremely knowledgable in, this one top my list. Now I'm an expert!

[Hotavio · Rating 3 out of 5]

This is one of those occasions where I wish I could give half stars, because I really enjoyed the book more than 3 stars.

How Sex Works was a First Reads that delving into a foray that I don't typically read. If I was well versed in the science of sex, I may not have been as impressed. But I truly believe that it would be hard to make the subject boring and How Sex Works is definitely not that.

The book covers a range of facts and curiosities, starting with Health class basics and later hitting on mysteries of sex such as the female ejaculation, venereal diseases and their adaptations, the sceince of love, hermaphroditism, among other related topics. The key theme being natural selection and its role, through sex and courtship, of propogating our species. There are many interesting points brought up in the book and the author makes mention of several scientific studies, many recently in progress, to explain things that we normally just take for granted.

I particularly found the scent and its role in relationships to be interesting.

Definitely better than the 'Birds and the Bees' lecture! The book is about the right length too, so as not to get bogged down by the subject, but enough to satiate the occasional thirst for the topic.

[Shana · Rating 3 out of 5]

How could I not read a book with that sort of title? Much of the information was a repeat from other books I’ve read, but Moalem also covered a lot that I appreciated, such as a chapter on homosexuality. My main grudge with books like these is that they’re so focused on reproduction that they tend to ignore the fact that desire doesn’t necessarily always follow reproduction, even if we’re biologically hardwired to be a certain way. I just don’t buy all that stuff, and Moalem writes about studies being completed on the function of homosexuality in society and in the animal kingdom. It was nice for once to have someone acknowledge the fact that not everyone is heterosexual. In any case, if you’re looking for a fun read that will help you come up with some great conversation starters (my coworkers have heard all of this by now), then pick this up. But a word of advice: skip the STI chapter. I found it hideously boring. The rest of the book kept it interesting with random facts but that one chapter just read like a health book, and not a very good one at that.

[Mark · Rating 4 out of 5]

+ Sharon Moalem. How Sex Works: Why We Look, Smell, Taste, Feel and Act the Way We Do I give this one 4 stars. Moalem is a neurogeneticist whose writing about sex is almost as fun to read as the genuine article is itself! In nine chapters, he presents an evolutionary history of human sexuality that is engaging and written in an easily readable style. Some readers may think it too lightweight and lacking in depth. It is, undoubtedly, a work of summary, giving an overview of the latest thinking and research (as of its publication in 2009) in human sexuality. I found it fascinating and don’t mind the breadth of approach, anything that attempted to be in any more depth would get bogged down and the scope of coverage would suffer.

[Jose Luis · Rating 5 out of 5]

Buen libro para iniciarse en la ciencia de la sexualidad, ameno y entretendio y bien documentado.

Recoge los principales avances en los estudios sobre sexualidad humana de los últimos años. Una revisión de referencias constatan la consulta de la mayoría de trabajos en biología y medicina realizados sobre la evolución del sexo.

Empieza con un repaso a las cuestiones del volumen de los senos femeninos y del tamaño del pene. Continua con la neurobiología de la atracción, la elección de pareja y las enfermedades de transmisión sexual. La homosexualidad, lejos de ser una excepción humana, se constata como muy habitual en el reino animal.

La tecnología sexual ha hecho y hará que cambiemos nuestro comportamiento, pero ampliar los límites de la ciencia del sexo no tiene sentido si las personas no poseen el conocimiento necesario para disfrutar de sexo placentero, satisfactorio y seguro.

Vale la pena leerlo.

[Miriam Pia · Rating 4 out of 5]

OK, I liked this because it reviewed some of what I had learned as a kid in sex education - glad to be part of the comprehensive sex education through the school [health class, fyi] as well as through the church AYS [that's AYS & OWL if you happen to need a program] and The Joy of Sex etc..mixed together with stuff I actually didn't already know. Its nice to learn new stuff and the occasional review really does help prevent 'forgetting what we've learned'.

Now, please understand that I was an avid fiction recreational reader and didn't read nonfiction that hadn't been assigned by a teacher until I was ...I think over 30 years old - but at age 28 I still had teachers [grad school professors] assigning me nonfiction.

So, I bought the book months before I actually started reading it and I took it very slowly and I did actually really like it.

[Traci Nigon · Rating 3 out of 5]

It's like a sex-ed class for adults. Lots of info you'd probably already know, but also some really interesting fun facts for you to throw out at parties ("Hey, Steve, did you know that babies can lactate?"). Also, it felt kind of jumpy, and a few areas I would have found interesting were sort of glossed over, like the fact that in rare cases babies have developed entirely outside of the uterus and still been delivered (via C-section). As a woman who has never been pregnant, I would like to know where, specifically, a small child could grow in my body if not the uterus. Finally, the book could have used a better copyeditor, and I don't see why the chapters were all song titles, but overall it was a fun read that took the science of sex, anatomy, and evolution and put it in words the average person could understand.

[elita · Rating 3 out of 5]

I'd give this book 3.5 stars if I could. I found it really enjoyable and interesting, but if you've read any of a number of other books on the topic, you've pretty much learned everything already. I mean, there's only so much you discuss in a book on sex. A whole chapter dedicated to the G spot just felt overwrought at this point. However, Dr. Moalem does have a way of taking complicated concepts and making them accessible to lay people. I really loved the chapter on the power of smell. I think we all know already how powerful the sense of smell is, but it kinda validated my obsession with the way my guy smells for me. Sometimes I've wondered if I am weird for needing to sniff him so often, but it's just biology, baby and it means I picked a good mate!

[Courtney · Rating 4 out of 5]

So, I really enjoyed the first half of this book. While the author is no Malcolm Gladwell, he does a good job recounting the results of some very interesting recent studies. In particular, I found the sections on sexual orientation and attraction very interesting. Unfortunately, the second half of the book read a bit like the syllabus of a high school health teacher. There were still some interesting bits even in this section, but it wasn't nearly as interesting. Then again, if you haven't learned much about the make up of the reproductive system or about STDs etc, then you might still appreciate this section.
All in all, I'd recommend this book. But for most people in my age group, I'd probably tell them to skip the last 1/3 to 1/2 of the book.

[Jay · Rating 4 out of 5]

Moalem takes the time to scientifically debunk a few myths; confirm a few others; and also leaves the reader room to pursue their own positions by presenting arguments on both sides of the discussion. The chapters and the content are all well organized and the material is accessible for the non science buff. Although I felt--a few times--the author's style reached for the lowest common denominator of comprehension; I think Natalie Angiers writing style is the standard to which I am comparing this author to, perhaps unfairly. However the topics were all relevant and provided plenty of new insight into subjects we all think about but then are too busy/lazy to follow-up on.

[Rae · Rating 3 out of 5]

A smart and seemingly credible book that didn't piss me off at all, surprisingly. Most interesting theory presented was: how being on hormonal birth control makes your body think you're pregnant which also changes your sense of smell to crave the pheromones that are similar to your own, as opposed to dissimilar when you're not pregnant, and therefore you could potentially end up with someone who under ordinary circumstances you wouldn't (and it kind of makes sense as one of my friends tried to get on hormonal birth control but then couldn't stand the smell of her boyfriend) anyway, it's one of the better of this type of book that i've read, so check it out.