The book is written in form of questions asked by people and those questions are followed by author's answers. Most of the questions and answers are repetitive and not very insightful, but regardless, I found some gems within the answers.
Fun fact 1:
Certainly, by four or five years of age children are using body language associated with their gender.
Fun fact 2:
During the World War II in England, there was a misunderstanding between English girls and American soldiers. The girls as well as the soldiers considered one another too fast. The impasse originated in the perception of the first kiss. In England, the first kiss was given after a long while, so it was customary to go to bed with a man shortly after the first kiss. Meanwhile, American soldiers were used to exchange kisses between friends, and they expected a long period of time before they would go to bed with a girl after kissing her.
Fun fact 3:
Human kiss could be derived from sharing food. Similar behaviour is common in the apes.
Fun fact 4:
The origin of a handshake can be found in the time when men carried weapons. Offering a stretched hand and grasping it guaranteed that neither of men had a concealed weapon in that hand. Handshake was thus a sign of peace.