I have got to think about something other than politics...
Global statement: It is better to have one sex predominate rather than have near-balance. But it is not good to have one sex exclusively for your cooperative group either.
My job is structured around a team approach. A dozen patients, all in crisis, and we meet for 90 minutes each day to review each of them daily. That's seven minutes each plus interruptions and one-liners, which isn't much if it's your crisis we're dealing with. But those 90 minutes set the course of the rest of my day. Concision and camaraderie are of enormous importance.
There are 5-8 players every day, plus student observers about half the time. Most are regular daily players, but because nursing and rehab works weekends, we have mix-and-match coverage people fairly regularly. I have done this for a long time, and have been on teams that are all or nearly all male, and teams that are nearly all female. When one sex predominates for any length of time I will kiddingly point it out. Boy Team. Girl Team.
The ideal is to have two of one sex and the rest of the other sex. Neither gender does well when it gets the whole culture to itself, and having one female among males or one male among females is usually not enough to change the prevailing culture. Even for a dominant personality like mine, outnumbered is outnumbered, and being on Intense Girl Team for too long gets wearing.
But an equal balance turns out to be worst of both worlds, and no fun at all.