These thoughts come without my Christian perspective - I merely describe the debate with a few pointers in a deliberately neutral way. If I get round to it, I might post some explicitly Christian and theological reflections on the debate. For now, a weeny annotated bibliography will do.
If you want something really radical to read, you should try Anne Fausto-Sterling, Sexing the Body: Gender Politics And the Construction of Sexuality (
So, to ask 'are sex and gender different?' is actually already to be asking a loaded question. Psychologists (see the chapters by Money and Maccoby in Reinisch et al, eds, Masculinity and Femininity: Basic Perspectives (New York: Oxford University Press, 1987) will discuss the question from a slightly different angle.
Regarding a nature-nurture discussion, Anne Moir & David Jessel, Brain Sex: The Real Difference Between Men and Women (London: Michael Joseph, 1989) gives an argument about 'essential difference', so that you have the other side of the picture from the recent feminist works (like Fausto-Sterling, above, and Barnett & Rivers, below). Also browsing Simon Baron-Cohen, The Essential Difference: men, women and the extreme male brain (
Regarding the effects that concepts of gender have, there is some good evidence in Rosalind C. Barnett and
Most of these authors tend to overstate their case in one way or another. Having read rather a lot of essentially similar works it's pretty clear to me that biology and culture both play a significant role! The final chapter of Lesley Rogers, Sexing the Brain (
I think your question about equality being 'measured by power, money and politics' is very important. This is certainly a major plank of the feminist movement, but I am not convinced it's the best way to go about things. To keep it simple, the liberal, modernist conception of the person as an autonomous quasi-spiritual ethical blob (think Kant) does not do justice to the fact that people are different not least because of bodily differences. So, a project that tries to flatten this out and make all adult humans exactly the same is not going to work terribly well. For an interesting feminist meditation on this that is open to the idea of difference, see Selma Sevenhuijsen, Citizenship and the Ethics of Care: Feminist Considerations on Justice, Morality and Politics (Routledge: London, 1998).
Hope that helps…