Warning - majorly cynical opinions below.
I have short circuited many abortion discussions with "pro-choice" folks by making the following observations -
1. Abortion statistics indicate that abortion mostly kills future Democrats. In fact, some minority leaders consider abortion to be genocide targeted at minority communities. Most minorities vote Democrat as do most single white women.
2. Planned Parenthood's vision of a nation with "abortion on demand", combined with getting more Planned Parenthood facilities, abortion clinics and free birth control into heavily Democrat, inner city communities, will reduce future Democrat numbers by the millions. Of the millions of future voters who have already been snuffed out by abortion, a large majority are most certainly Democrats.
3. This aspect of Democrat population control is a "silver lining" in the otherwise dark world of abortion.
When I portray abortion as Democrats "eating their young", I usually get a much different reaction from "pro-choice" folks than when I speak to the morality of abortion. The former seems to hit home. The later, not so much.