I don't have it at hand unfortunately, thus the "IIRC". If you find it, please post it so I can write it down though. As a starting point, I'm pretty sure it was posted on Slashdot a few years ago, possibly around the time that astronaut went nuts and road tripped across the US in a diaper to confront another astronaut she had a thing with.
This (http://history.nasa.gov/SP-4411.pdf) report suggests that mixed groups are likely more productive and cohesive than all-male groups. It doesn't mention all female groups though.