Yet I suspect Milton Friedman did more to end the draft than the accomodating Baez sisters, which I guess suggests something about the relative persuasiveness of certain organs.
The excruciatingly pedantic former logic instructor in me cannot resist pointing out that this is a rather stronger (and more ridiculous) claim than “I only sleep with Democrats,” as it sets out a sufficient condition for girls saying yes, rather than a mere necessary condition for a girl saying yes. But it is also pointlessly weak, if it is given a not implausible interpretation as “For every boy who says no, there is some girl who says yes.” (Don't think you're getting Joan Baez!) But this follows trivially from the truth that “For every boy, there is some girl who says yes” — especially if money is involved. But there's no denying it's a damn pithy slogan!
[Thanks to Anonymous Coward for the reminder and Brink for the link.]