Fred Reed said something along those lines. When you have a combat unit of 12 men, you have a “band of brothers” sort of thing. When it is 11 men and one woman, you have 11 men competing for the favors of the one woman.
That is a really bad thing.
Side Story: As we drew near to returning home after Gulf War I, the females, all three among 800 guys, became, what is the word, ‘bit#hy.” When someone commented on this another guy said; “Well, it's because they realize that in another few weeks they will be ugly again.”