Rayleen -- Let me ask this: if there was no gender differentiation in clothing, do you think the impulse to present female would go away? The question is a little complicated by the fact that on this forum we have people who say they are crossdressers but not transgender, but if you accept that crossdressing is a kind of transgender behavior do you think unisex clothing would really stop it?
I'm pretty sure that I've read about societies where the sexes DO dress alike and yet transgenderism still exists. The trans folks just focus on hair or body modifications or whatever attribute is most associated with women in their culture.