The fact that we are still arguing about this says something deeply disturbing about our culture. While serving in the military is not my idea of a fulfilling career, it is for many people, including many women. Keeping women from being officially assigned to 'combat' is just one more way to keep women from advancing careers. The motives for keeping women out of combat are the same as those for rejecting equal pay legislation.
I believe that killing another human being (even in combat or self-defense) is damaging to one's soul. But this is as true for men as it is for women. If women become more involved in those 'front line' tasks they will likely start suffering the psychological/emotional/spiritual trauma with the same frequency as men. While I would not wish that on anyone, male or female, it might produce a rethinking of how we treat our veterans. The same attitudes that cause some people to insist on keeping women out of 'combat' may make them more open to recognizing emotional and spiritual trauma in women — and eventually acknowledging it in men too.
Keeping women from being assigned to combat is not just unethical, it's counterproductive and needs to stop.