Who's the Favorite?: The Loving, Messy Realities of Sibling Relationships

by Catherine Carr

An award-winning documentarian and host of the popular Relatively podcast delivers the definitive book about siblings—often the longest relationships of our lives, and the least acknowledged.

For many people, relationships with brothers and sisters last a lifetime, spanning decades. Sibling relationships precede friendships or romances and outlast most connections to parents. Eighty percent of us have brothers and sisters who share our DNA and are often the unique keepers of our intimate histories. Our siblings can be our allies and our competition, our tormentors and our protectors, our best friends and our enemies. Research has found that these relationships are just as influential to our development as parenting.

Documentarian and celebrated podcast host Catherine Carr—herself a middle child—became convinced of the profound importance of sibling relationships. In Who's the Favorite?, she takes us on an unprecedented journey through some of the universal themes of designated roles and labels, friendship and enmity, shared trauma, family language and jokes, and separation and estrangement. Drawing on over seventy conversations she has had with pairs of siblings for her podcast, new research, studies by psychologists, and fascinating depictions in popular culture, she sheds new light on these vastly underappreciated relationships that profoundly affect our lives—relationships that are formative, vital, and full of clues about how to make sense of how we get on with others.

Part journalistic deep dive, part storytelling, part pop cultural critique, this conversational, illuminating, and endlessly absorbing work is a long overdue look at our sibling relationships and how they define us.

Supplemental enhancement PDF accompanies the audiobook.

Genres: Nonfiction, Psychology, Self Help

Audible Audio

Published April 7, 2026

Reviews

[Donna Williams · Rating 3 out of 5]

I’m the youngest of 3 sisters and I’ve always been fascinated by discussions around birth order. The author introduced some new concepts to me: the idea of vertical vs. horizontal sibling relationships and something called “glass” siblings. It was interesting to know that when there is a loss of a sibling, the grief of the sibling(s) left behind is often not addressed and not tended to. The focus tends to be on the parents when there is a loss of a child. That was eye opening for me!

I enjoyed when the author shared specific details and dynamics within her own family. I would have wanted more specific scenarios and less passing references to studies done by “Dr so and so” and what “Dr so and so” said. My overall impression is that I should check out Catherine Carr’s Podcast “Relatively” - I might enjoy that even more than this book.

[Patricia · Rating 5 out of 5]

Really interesting. I wish it had gone deeper into some of the studies cited (very curious about the methodology on some), but I understand the book is trying not to be too technical. I learned a lot.

[Katie Salmon · Rating 5 out of 5]

A fascinating and empathetic look on sibling relationships in all shapes and sizes.

[Charlotte · Rating 5 out of 5]

Fantastic. Insightful, intelligent, funny and deeply moving, this is a totally charming book that will gently lead you to consider sibling relationships in an entirely different light.