William Saletan has an interesting Op-Ed in today's Washington Post, arguing that technology is making first-trimester abortions increasingly easy, while making people more ethically-troubled about second-trimester abortions. He suggests the great abortion debate could be mostly resolved by easy access to contraception and early-abortion methods, while later abortions become discouraged and rare.
I agree that the physical similarity of an older fetus to a baby will increasingly make a distinction in people's minds about the ethics of abortion in those cases, although what I think should really matter is brain function and development, not body shape. Technology could take this issue one step further though.
Saletan writes about how medical advances have pushed fetal viability to ever-earlier stages. A point he doesn't touch on is how this could ultimately solve the infringement of bodily autonomy, where women are forced to remain pregnant for the sake of the fetus. I think the day won't be that far away when women can end (abort) their pregnancies any time after the first twelve weeks without killing the fetus. Women then would retain bodily autonomy, but lose the right to kill the fetus after the fetus reaches a level of development where it's considered to have some innate moral value.
So the end result would have legalized abortion in the first trimester, and women would also have the right thereafter to end their pregnancy at any time, but not to kill the fetus. I expect this solution would have plenty of problems, not least of which is the expense and failure rate of the new technology, but it might be a significant improvement over the present.