Over the last few weeks, I've been at a few "Women in _____" events. A typical question at these events is, "What's the advantage of being a woman?" and I hear the same, short-sighted answer, "I stand out because I'm the only woman in the room." Here's what's wrong with that.
If women believe the major/only benefit of being a woman is that they're the only one - they are not motivated to let other women in. This is actually a pretty big issue. In the whisper network, we call women who perpetuate this notion "the old guard."
When teams of men are faced with questions and scrutiny over why they have no women on their teams - they will often hire just one and stop at that. It's called moral licensing.