Andrew Sullivan directs us to the interesting discussion at Bleeding Heart Libertarians, "why aren't more libertarians women."
In the comments beneath the article, Virginia Postrel offers a very smart retort:
Imagine you are a social scientist asking this question. How might you start? One way would be to ask why *a person* might become a libertarian and, even before asking that question, why *a person* might be drawn to a systematic political philosophy/identity rather than the more common combination of self-interest (not only economic or even personal but ethnic, communal, familial, religious, whatever) and issue-by-issue instincts (something must be done). What is the influence of temperament? Life experience? Historical context? Professional culture? Religious background? Parental influences? The number of possible factors is enormous.
Having accounted for why a small percentage of the population is drawn to systematic ideologies (for lack of a less-pejorative word) and why a portion of that subpopulation is drawn to libertarianism, you could then look at how men and women--as well as other ways of subdividing the population--might differ. These are empirical psychological and sociological questions and would require some careful research, not just speculation that starts from the presumption that people become libertarians because they are good, smart, rational people who see the light. These questions also cannot be answered by evolutionary psychology, which is valuable in its place but isn't the be all and end all of psychological understanding.
If you don't know why people become libertarians in the first place, it's silly to speculate on why women and men might be different. Of course, people LOVE to talk about sex differences, so if this is pure entertainment I'm just being a spoil-sport--like one of those men who insists on trying to analyze and solve problems when the wife just wants to vent.