If, at this point, you're as frustrated as me, you might be wondering what we do know about female orgasm. Well, we're closer to knowing why they're so few and far between during sex. In a paper published online this January in Hormones and Behavior, Lloyd and Wallen found that the farther away the clitoris is from the urinary opening, the less likely it is that the woman will regularly achieve orgasm with intercourse. If this holds up in future experiments, Lloyd says, it would establish that a woman's ability to have an orgasm during sex rests on an anatomical trait that likely varies with exposure to male sex hormones in the womb. "Such a trait could possibly be under selection," she says, "but this would have to be investigated. So far, no selective force seems to appear."