I always looked at it this way: I'm pro-CHOICE.
I will just as adamantly defend a person's right to have as many children and with as many varying disorders as they so want with as much fervor as I will defend a woman's right to a safe abortion.
Do I think that Duggard woman is crazy with her 20 kids? Yup. But, that's her choice. Do I think it's right to give birth to a baby with a lethal disease such as Tay-sachs or Edward's syndrome, knowing they will have a very short, painful life? No. But, I would never tell a woman in that situation that they even "should" abort. I understand that for some women, ending a wanted pregnancy is more psychologically traumatic than "letting nature take its course."
Every woman should get to choose what she wants to do with her body and her pregnancy. And yes, for me it is important to support abortion rights. I'm 100% pro-choice, no questions asked. I terminated 2 pregnancies that most people would see as perfect situations: happily married, financially secure, supportive family, probably healthy fetuses (assumed due to being under 25, but will never be known for I terminated before 7 weeks both times). The part that wasn't perfect though was that I wasn't trying to get pregnant, and I had no desire to have a child. Luckily, despite my young age and CF status, I've managed to get my tubes tied. Even that has a 1 in 400 failure rate. If I happen to be that unlucky, I would still hope that I would have the right to have a safe abortion. If that ever gets taken away from women, I'm not sure I could feel secure in this country anymore. I need to know that I have a choice, and that my body is my own and not subject to the opinions of other people.
I'm not anti-life, I'm pro-choice. There is a difference.