For most women, passionate desire languishes in the lower reaches of the list, somewhere below 'to get presents from him,' 'to shut him up' and even 'for fun'.
(It's striking that there's no mention of 'Because I was drunk', yet millions of men would testify to the fact that their chances sky rocket when a woman has had a few glasses of wine.) Given a choice, girls prefer tall men with symmetrical features and deep voices - which suggests the female sex drive is, above all, evolutionary, because they believe such men will provide them with healthy children.
But once we've realised he's lacking in other areas or the passion has ebbed away, the reasons to have sex become far more mundane, or even acquisitive, such as 'So he'll take the rubbish out' or 'Because he took me for a meal'.
In this light, feminism's eagerness to persuade women to have sex only when we experience knee-trembling desire seems naive.
Endless books and articles have been written extolling our right to enjoy earth-shaking orgasms amid a whirring Rolodex of thrilling positions.
But they overlook the elephant in the room - long-term, a woman's sex drive is rarely equal to a man's.
Not long ago, I was talking to a single friend about her recent conquest.
'To be honest, I only slept with him out of politeness,' she admitted.
I was not surprised - as women's labyrinthine reasons for having sex go, that's pretty basic, stock-in-trade stuff.
Perhaps men will find that a little shocking, depressing even. Indeed, they wouldn't if we hadn't all been fed a Utopian myth that men and women have sex purely because they're crazed with lust for each other - or, in a long-term partnership, because they still adore each other.
Any woman past the age of 16 knows what idealistic nonsense this is - and finally, there's research to prove it.
As the Mail reported yesterday, in a new book, Why Women Have Sex, 1,000 women were interviewed about their real reasons for saying 'Yes' when they could have said 'No'.
Boredom, winning favours and to get rid of a headache were high up the list.
These results suggest that comparing the intricate physiological and emotional strata of the female sex drive with the blunt male urge to 'Just do it' is like comparing a tin opener with the Large Hadron Collider.