Not sure if this is generally true or to what extent, but I'm a male who's great at math and iffy at English (I'm in honors courses, just not as good at it as other things). Hell, my 8th grade math class said on a few occasions I should teach the class, though in all fairness, it was a good bit because our teacher after the first one retired was crap.
Other than that bit of ego-inflating, I'll say that in my experience it's not really a subject thing, there are just a group of smart girls who get in honors and AP classes.