Before I became a Catholic, I was pro-choice. I would not have become Catholic had I not been able to accept the Church's views on this matter, so obviously my opinions have changed a lot; I am now sorry for my attendance at the one abortion rights rally I attended and for any influence I may have had on anyone else's views. But one thing I can say in my defence (sort of) is that at least I was genuinely pro-choice. I believed that only the pregnant woman herself should have the right to decide whether or not to end her pregnancy, and I believed that only the individual in question should determine whether he or she would be sterilized. Forced abortions and sterilizations horrified me.
I make a point of saying I was genuinely pro-choice, because some people in today's society say they are pro-choice, but really aren't. The most obvious example is people who claim to be pro-choice, but who refuse to condemn China's coercive population control program or, worse, approve of it--people like Molly Yard, former president of NOW, whom the Associated Press is reporting has just died. But there are others. Parents who say they're pro-choice, but who force their teenage or college student daughters to abort. Judges who offer convicted women time off sentences if they agree to sterilization or insertion of Norplant. People who claim to be pro-choice and then grumble at who gets and stays pregnant. Or who talk only about the boons of not having children, while seeming to find it hard to fathom that many women would prefer to keep their children. Or who talk as if people who choose to have large families are doing something wrong. Or who don't want to hear others talking about abstinence or Natural Family Planning (or, in extreme cases, even the Fertility Awareness Method). Or who don't want pro-life people to be allowed to talk at all.
People who are genuinely pro-choice may not be where they should be in their views, but at least they're not forcing or subtly bullying women onto operating tables.
(For some interesting listening on China's population control program and American responses to it, listen to Steven Mosher, author of A Mother's Ordeal: One Woman's Fight Against China's One-Child Policy, talking to Marcus Grodi on EWTN's The Journey Home. The episode is dated 4/28/2000.)