Why do people say there's something wrong with asking. I'm a woman, and I'd want to know if it was some crazy number. I had a guy friend tell me that he had a friend who had sex with 60 something girls. Mind you, were 19 so his friend was in his late teens/early twenties as well. It was off putting to hear such a high number
Women say it's wrong to ask so they don't have to answer.
Men say it's wrong to ask because we're supposed to be "players" and "keep our cool" and let things come out. It's also best to remember that a good deal of posters here are 30+. IMO I can "let a female tell on herself" but the 1, 2, or even 3 episodes that slip out of her mouth may be about 3 out of only 10 sexual partners instead of an NFL roster...at my age (24/25) I can accept a woman with 10 bodies.
Meanwhile, the chick I ask outright might tell the truth about having 20 partners (which is too many), or tell me 20 when it's 35, or she might have only been with 3 but will tell me 10 because she may feel the need to keep up with me and come off sexually experienced (a good deal of people assume I have the option to sleep around).
The point is if it's important to an individual they should ask. If I feel like I'm heading into something serious/exclusive with a woman I'm asking. 10 years from now it may not be absolutely necessary to ask but I likely still will. If they find my question childish they probably are afraid to answer and I shouldn't be with them.