IMHO, there's only one really significant psychological gender difference,
namely "assertiveness". Due to evolutionary circumstance women are
*generally* less aggressive and individualistic than men. That's why they
are treated as second rate citizens in virtually every country of the world.
Assuming that this theory is correct, hormone treatments for all female
fetuses and (later on) genetic engineering should pretty much solve the
problem. The potential is there, it just needs to be seized. Once again,
technology is the equalizer.