Jared Diamond takes a hard look at the evolution of human sexual behavior in his carefully researched, funny, and insightful book, Why Is Sex Fun?

We all know what sex is good for; we wouldn't be here otherwise.

But why is the act of sex enjoyable? Why do we do it even when it doesn't result in pregnancy?

Few other species on the planet have sex just for fun. Our sexual behaviors differ from virtually every other mammal on Earth, let alone nonmammalian creatures.

After studying human groups around the world, geographer, professor, and author Jared Diamond decided to examine the reasons that humans are so different.

In Why Is Sex Fun? : The Evolution of Human Sexuality, Diamond delves into behavioral, genetic, and cultural research.

Diamond explains why menopause is unique to humans, why we tend to pair exclusively, why we have recreational sex, and why men don't nurse infants – but might in the future.