There's a plethora of reasons why there are fewer women comics.
One, is that girls are raised a certain way. They're encouraged to be nice, pretty, etc. They're not encouraged to be funny.
Second, becoming a female comic is extremely hard. Traveling on the road to work (where you make the money to pay your bills) is more dangerous for a girl traveling alone than it is for guys. i know a couple of friends, female comics, who were attacked while on the road.
Third, guys aren't welcoming to female comics. Many men dismiss female comics with "chicks ain't funny."
Fourth, subject matter. Chamburger says female comics have to be raunchier to make it - I disagree that they have to, but some do (Lisa Lampenelli, Chelsea Handler, Whitney Cummings). So, the subject matter they choose makes a lot of audiences uncomfortable. And, there are only so many variations on period jokes the hackier female comics can come up with.
Fifth, a comedy audience is made up, many nights, by couples dating. Women in the audience, in this dynamic, call the shots on funny. If a girl laughs at a comic, it's "okay" for the guy to laugh, as it shows a similar sense of humor and increases the chances of getting lucky. If a girl in the audience doesn't find a comic funny, and the guy is laughing uproariously, odds are good he's not getting any. And girls judge girls who are on-stage. If they're too pretty, they shut down and don't laugh, as she's a threat. If they're funny, and the guy laughs, it's a threat. A lot of women will tell you they don't find female comics funny. You would think shared experiences would win out, but it doesn't.
There are exceptions to all of these general observations, as well as arguments that can be offered against any of these points, but after 12 years on the road in comedy, I can tell you it's pretty accurate.
gelder