I just saw a TV show that kept saying "men take two minutes to orgasm, women take twenty." Like it was some established thing. I've also heard three and thirty.
On average, maybe? I've never done a survey. One of my friends has never had an orgasm, so factoring her into the average, women take infinity minutes to come. Myself, I don't think I could possibly hold out for twenty minutes unless you're measuring from the first kiss or something.
Actually, that makes me wonder when you measure from. Are we talking from the start of sexual activity (whatever that means), or from the start of genital stimulation, or from the start of short-strokes intense genital stimulation? Because really, having an orgasm takes me about three hours if you count dinner and drinks.
That's facetious. But it's not facetious to say that when you get to the short-strokes, I'm going to come a lot faster and more reliably if I know you better--so dinner and drinks really were part of reaching orgasm. Fuck, if you count everything that contributes, sometimes it's taken me two years to reach orgasm with a guy. And slutty as I am, it's never taken so little as twenty minutes. If I've never laid eyes on you before and you just walk up and start the G-spot stimulation--well, that's more a thought experiment than a sexual experience, but I'm guessing it would be just a bit harder to relax. I don't think most guys could do it in two minutes like that either.
It seems like the "ten times as long" platitude gets around less because of validity than because it reinforces stereotypes. Men are simple and slutty, women are unfathomable and frigid. Making a man come is merely a matter of consenting, making a woman come is a painstaking skill. Men give it up easy, women make you work for it. Woman, she is a meeestery. (Or if you want to be sort of feminist about it, "female sexuality is very complex.") A woman who gets off pretty fast just from plain old fuckin' doesn't fit that paradigm. And a guy who doesn't come from a couple minutes of straight-up cock-stroking every time--shit, maybe he's gay or something.
Anyway, all this is like saying "men weigh 180 pounds, women weigh 120"--maybe it's just an obnoxiously narrow social expectation or maybe it really is valid statistically, but either way I wouldn't take it shopping.