I don't think kaytay is really talking about equality in the above writeup. At least, by my definition, equality in general is whether two groups of people are treated the same by law and by society, not what characteristics they share. I certainly agree that women and men are different, whether for the reasons cited in kaytay's writeup, other behavioral reasons, or just pure anatomy -- but nonetheless they should be equal before the law. Whether they are "equal" in your choosing to be friends with one group or another isn't so much a function of what they are like, but how you see those groups and what qualities you value.