I would also like to add that the possibility that women may choose to obtain abortions if their children will have severe disabilities (or for sex selection or whatever) is, as Dana suggests, likely to be a major rhetorical strategy for the anti-choice lobby.
I really don't think so. I imagine large numbers of the "abortion is icky" and "pro choice for me but not for thee" crowds would see the abortion of children with severe disabilities as "good" abortions in many cases. I don't think this would be an especially productive strategy for the anti-choice crowd.