I think the way young women and young men are "socialized" into music in middle school and high school contributes to this, especially in their initial choice of an instrument when they start.
The "main" instrument of nearly all college marching band directors or high-level DC brass I've known was either trumpet, trombone, drumline, and sometimes a smaller brass section (e.g., mellis). Very rarely do they seem to be a woodwind player, a sax player, or do they come out of flagline or twirling.
Young men dominate the former while young women are more common in the latter. I think there are two reasons for this. Firstly, brass and percussion instruments are heavier. A sousaphone or bass drum weighs a lot more than does a clarinet or an alto. Secondly, trumpet, trombone, and etc. are loud, boisterous instruments compared to the more reserved, quiet woodwinds. I don't think you need to meet many teenage boys to compared them to their peer girls to guess which group is going to be attracted to which type of instrument.
Add in the fact many college marching bands and DCs don't march with woodwinds at all (or only with saxophones if they do) and that brass and drums really *are* a marching band (sorry to any woodies out there, but you're hard to hear outside... not your fault, but there's a reason you're generally charted in the back of the field, you're there to make the band bigger and even the male/female ratio out, not to crank up the decibels)...
...and you end up with a pool of mostly men heading into those leadership positions.
en.wikipedia.org
