It's common knowledge that reading books makes you wiser. I read a lot of books, but there are obviously a lot of things I didn't know. Especially about sex. I had to read the latest NYT Book Review to learn that Galen of Pergamum, the great physician and medical researcher of antiquity, was one of many learned men of his time who believed that women had to have an orgasm during sexual intercourse for conception to occur. For 1,500 years this was the scientific consensus. And today it is still generally believed that women are naturally less libidinous than men. True or not? According to Daniel Bergner (What Do Women Want? Adventures in the Science of Female Desire. Ecco/HarperCollins Publishers) it depends where you meet. In the 1970s, a psychologist and neuroendocrinologist named Kim Wallen noticed that the sexual behavior of rhesus monkeys was affected by the size of their cages. In close quarters the monkeys went at it like mad, and the male seemed to initiate sexual activity, which in turn seemed to confirm the prevailing idea that female monkeys were entirely sexually passive. But in larger cages, as in the wild, the females were the ones who chose their partners and initiated sex by following the males around and touching them demonstratively. The small cages, with their forced proximity, reduced monkey sex life to intercourse, obviating all the mating rituals in which female lust was the essential factor that set sex in motion. After Wallen’s observations, primatologists started seeing evidence that many kinds of female primates initiated sex, while their male counterparts pretty much sat around waiting for the ladies to take an interest in their erections. Amazing, isn't it. You never stop learning.