Admittedly, homo sapiens has the least amount of gender differences of the great apes, from what I remember.
Humans are still evolving, though in ways that we don't usually notice as we can't observe our past as objectively as we can with other species.
Sexism as a whole might well be a remnant from our ancestry where the social community might well have been somewhat similar to chimps or bonobos (Tyrannical male and stuff). However, this shouldn't be an argument for humans to just give up on equality. After all, we have pissed in the eye of every other "natural" process so far, why not improve on the equality of genders too?
I'm not making much sense, sorry.