Why is Sex Fun?

by Jared Diamond

The key to understanding human sexuality is to recognize that it is a problem in evolutionary biology.

-- from the preface


This is a great book. Diamond's tone reminds me somewhat of Bill Bryson. He's a scientist, though, not a travel writer, and as a scientist, he certainly asks some interesting questions about topics people generally take for granted. For example:

p. 42: Among seahorses it's the male rather than the female that becomes pregnant; why is that not also true for humans?

p. 65: Why don't women give clear ovulatory signals, like most other female animals, so that we can restrict sex to moments when it could do us some good?*

p. 89: What are men good for?

p. 104: (regarding human menopause) How could natural selection possibly result in every female member of a species carrying genes that throttle her ability to leave more descendants?

p. 142 (comparing male human endowment to that of the apes) Are those extra couple of inches of the human penis a functionally unnecessary luxury?

These are good questions. They get even better answers. He manages to poke holes in some of our most basic assumptions about human behavior while simultaneously using these assumptions as a source of humor. So the reader is laughing and looking at things in a new light all at the same time, an edifying and enjoyable experience.

Also, unlike several biographies I could mention, this book is quite short.



*Charmingly, he prefaces his discussion of the question as follows:

By now, you may have decided that I'm the prime example of an ivory tower scientist searching unnecessarily for problems to explain. I can hear several billion of the world's people protesting, "There's no problem to explain, except why Jared Diamond is such an idiot. You don't understand why we have sex all the time? Because its fun, of course!"

Unfortunately, that answer doesn't satisfy scientists.