237 Reasons Why Women Have Sex

Do you want to know why women have sex with men with tiny little feet? I am stroking a book called Why Women Have Sex. It is by Cindy Meston, a clinical psychologist, and David Buss, an evolutionary psychologist. It is a very thick, bulging book. I've never really wondered Why Women Have Sex. But after years of not asking the question, the answer is splayed before me.

Meston and Buss have interviewed 1,006 women from all over the world about their sexual motivation, and in doing so they have identified 237 different reasons why women have sex. Not 235. Not 236. But 237. And what are they? From the reams of confessions, it emerges that women have sex for physical, emotional and material reasons; to boost their self-esteem, to keep their lovers, or because they are raped or coerced. Love? That's just a song. We are among the bad apes now.

Why, I ask Meston, have people never really talked about this? Alfred Kinsey, the "father" of sexology, asked 7,985 people about their sexual histories in the 1940s and 50s; Masters and Johnson observed people having orgasms for most of the 60s. But they never asked why. Why?

"People just assumed the answer was obvious," Meston says. "To feel good. Nobody has really talked about how women can use sex for all sorts of resources." She rattles off a list and as she says it, I realise I knew it all along: "promotion, money, drugs, bartering, for revenge, to get back at a partner who has cheated on them. To make themselves feel good. To make their partners feel bad." Women, she says, "can use sex at every stage of the relationship, from luring a man into the relationship, to try and keep a man so he is fulfilled and doesn't stray. Duty. Using sex to get rid of him or to make him jealous."

"We never ever expected it to be so diverse," she says. "From the altruistic to the borderline evil." Evil? "Wanting to give someone a sexually transmitted infection," she explains. I turn to the book. I am slightly afraid of it. Who wants to have their romantic fantasies reduced to evolutional processes?

The first question asked is: what thrills women? Or, as the book puts it: "Why do the faces of Antonio Banderas and George Clooney excite so many women?"

We are, apparently, scrabbling around for what biologists call "genetic benefits" and "resource benefits". Genetic benefits are the genes that produce healthy children. Resource benefits are the things that help us protect our healthy children, which is why women sometimes like men with big houses. Jane Eyre, I think, can be read as a love letter to a big house.

"When a woman is sexually attracted to a man because he smells good, she doesn't know why she is sexually attracted to that man," says Buss. "She doesn't know that he might have a MHC gene complex complimentary to hers, or that he smells good because he has symmetrical features."

So Why Women Have Sex is partly a primer for decoding personal ads. Tall, symmetrical face, cartoonish V-shaped body? I have good genes for your brats. Affluent, GSOH – if too fond of acronyms – and kind? I have resource benefits for your brats. I knew this already; that is how Bill Clinton got sex, despite his astonishing resemblance to a moving potato. It also explains why Vladimir Putin has become a sex god and poses topless with his fishing rod.

Then I learn why women marry accountants; it's a trade-off. "Clooneyish" men tend to be unfaithful, because men have a different genetic agenda from women – they want to impregnate lots of healthy women. Meston and Buss call them "risk-taking, womanising 'bad boys'". So, women might use sex to bag a less dazzling but more faithful mate. He will have fewer genetic benefits but more resource benefits that he will make available, because he will not run away. This explains why women marry accountants. Accountants stick around – and sometimes they have tiny little feet!