Men dominate the field of music, no matter what genre. In Charles Murray's book Human Accomplishment, only one female shows up on the list of eminent Western composers and ranks near the bottom. All the way down in popular music we see the same pattern. The obvious answer is that there's some cognitive skill regarding music that men are naturally more endowed with, given that females seem to do OK writing novels.
Still, many whose explanations don't rely on overt discrimination against women tell stories about how women could excel as composers or rock musicians -- they just allocate their time differently and thereby don't log all those necessary hours of practice to make it big. Child-bearing is an easy example of something that would keep them from focusing as single-mindedly on musical creation as men do.
But tonight at the dance club I noticed something very strange -- there was a female DJ pinch hitting for one of the regulars. It never occurred to me before, but there are almost no female DJs on the radio or in nightclubs. The argument about not being able to devote most of your time to creating music due to other constraints, while not persuasive, at least it gets off the ground. But forget about composing and performing -- women can't even pick music that's already been made!
Sure you need to put in the time to build up a mental library of songs in order to piece together a good playlist, but this isn't so labor-intensive that it's either that or raising kids. It all depends on how good of an ear you have for music -- what songs to include, and in what order, is not a simple matter for most people (as you'll find out by listening to the playlists on their iPod). Those who have a knack for music, though, can churn out a decent playlist without much effort. They're the ones who get gigs as DJs; they typically have a day job, which drives home how little of your time is required if you've got a good ear.
The market for DJ services is viciously competitive, so discrimination will be close to non-existent. If a nightclub owner favored a poor DJ just because he was male, he'd go out of business in a couple of weeks. There's also no old boys' club for DJs in most genres -- techno, industrial, hip-hop, etc., which rely more on DJs than on live bands, all began a decade or more after the women's liberation movement of the early 1970s. There's no cabal of dudes dressed like the Monopoly guy who control entry into the gothic DJ syndicate. Moreover, most of the audience on the dance floor is female, so it's not a matter of having to serve the tastes of the opposite sex who you don't understand as well as your own. And the DJ booth is insulated from the rest of the room, mitigating stage fright.
We conclude that men tend to have a better sense of what sounds good in isolation and especially what songs and in what sequence will create the most pleasing gestalt. Some girls get it -- they typically wind up working at used record stores -- but in general they're going to pay too little respect to the Rolling Stones relative to the Beatles, to T. Rex relative to David Bowie, and to Schubert relative to Chopin.
Women overall have a tougher time than men stepping outside of what immediately and directly speaks to them and appreciating culture that isn't exactly their thing but that anyone with good sense can still tell is good. The evolutionary cause of this is men's involvement in very wide social networks, while women have specialized in smaller, more closely knit circles. If you're schmoozing and making nice with people from other groups outside your close kin, you'd better be able to enjoy a wider range of culture, lest you offend them with your chauvinism and lose out on the fruit of all that social politicking.
The female DJ tonight did manage to slip this one into a somewhat contemporary-oriented playlist, which was a savvy move, though she was wearing a shirt and tie, so she probably has a masculine brain.