In the recent discussion of Fr. Roy Bourgeois and women's ordination, one thing I saw mentioned often in comments was the concept of "complementarianism" - the belief, usually religious, that men and women have different but complementary roles. You can find this in the catechism, and of course in JP2's Mulieris Dignitatem. Another term for this idea is difference feminism, the belief that men and women are ontologically different versions of the human being ....
The metaphysical foundation of this theory was developed by Dietrich von Hildebrand and Edith Stein, and later by Personalists like Emmanuel Mounier and Jacques Maritain. More recently, the theory was espoused by Pope John Paul II as a foundation for a new feminism. (see JP2's letter to women)
This reminded me of a lecture by Michael Kimmel, a professor of sociology at Stony Brook, about gender difference. Here's a quote from the lecture ...
"[W]hat we know in behavioral and social science is that on every available, every measurable trait, attitude, behavior, women and men are far more similar than they are different. That is what every social and behavioral scientist knows. There may be some small mean differences, but the real story in gender is that the variations among men, and the variations among women, are much greater than any small difference that you might find in mean scores between women and men .... There's something in our culture, something in where we are, who we are, that wants desperately to believe that there is some fundamental, irreducible difference between women and men. Now my argument to you tonight is not only that men and women are more similar than we are different on every available measurable trait, attitude, and behavior, but in fact we are also more similar than we are different politically - that is, there is no war between the sexes, no battle between the sexes, that in fact men and women can and should be allies .. the very things that women have identified that they need to live the lives they say they want to live are the things that we men also need to live the lives that we say we want to live."