Well, just look at who were on the podiums at the WEG....just as many (If not more) men than women.
DH does more dressage than jumping but that's only because his knee problems mean he gets sore when he's riding with short stirrups. I board at a dressage barn and the women clearly outnumber the men, but this isn't a professional barn by any means. When you start looking at professional barns, those numbers even out a little more. It makes me wonder where those men learn?