Your suggestion that bad behavior by all-male teams would be improved by the addition of women rests on a couple of assumptions that are not true: that women are inherently better behaved than men, and that women naturally see each other as being on the same team.
I have been through some really awful experiences in the workplace in the last few years, and some of the most egregiously abusive behavior came from another woman. Women can be incredibly cruel to each other, and this woman in particular seemed to have it out for other women. Women are not inherently saints, and they are not inherently kind to other women.
On the other hand, I have often, often worked on teams that were (except for me) all men, but by and large they were men who had mothers, wives, sisters, and daughters that they loved, and who therefore had no trouble relating to me with respect and affection. While it is true that some men treat women specifically badly, and that some men treat people generally badly, it is not true that men in general treat women badly. Quite the opposite.
It does take a moment, as a woman, to find your feet socially in an all male space. But does it not always take a moment to find your feet in any new space? I have generally found that what makes it go smoothly is the fact that we are all hackers. If anything, it is all the walking on eggshells about sexism that makes social integration awkward at first. People are trying to figure out how they are "supposed" to behave around me, worried that I will be aggressive socially and legally. When we focus on the work we do together and the love we have in common for the field, we become friends naturally and get along well.
I myself think all the hand-wringing over demographics has been a waste of time at best and counterproductive at worst. I think it makes more sense to focus on developing virtue, civility, and good leadership among the people who find themselves here.