I've posted in a number of forums where I have identified myself as female.  I can't remember a single one where I was trolled by someone identifying as a woman.  I guess some could have been women pretending to be men but the vernacular always seemed much more male.  I did have women disagree with me but never in the vulgar, bullying, intimidating way that those identified as men chose to. On "mommy" sites however I would agree that women can be vicious but again, the style of trolling tends to be different than what is usually received from men.