http://en.wikipedia.org/wiki/Charles_manson#Childhood
I read an thouught-provoking story of a Christian parents, who during pregnancy found she would be born with Down's Syndrome. They already had several children. The doctor informed them the child needed a commitment to her care for the rest of her life, beyond the life of the parents.
The parents had a meeting with their children and explained they were making a choice that might affect their lives as well. They were undecided about terminating the pregnancy. There is more than one way of looking at this situation, not all Christians are fundies.
The mother told them if they ended the pregnancy, that the child would go to be with God sooner rather than later and what did they think. The children thought it over and said they would commit to taking care of their baby sister for life.
That story struck me because it didn't present the body as being all there was, but an eternal soul that would survive whether in the body or not, which fits some Christian beliefs. Others feel that the child not being born into a physical body is being denied everything, which is a somewhat materialist viewpoint. But not everyone does.
That is not always the case that such decisions are made with a happy outcome. And the cutting away of Medicaid, food stamps and assisted housing and the like, are the lifeline for many of these people. And some people do not have extended families that agree to care for these children, especially if they have multiple disabilities or the family is older.
Things are not how they are shown on television shows where disabled children and families live happily ever after. There can be marital breakups, physical and sexual abuse, poverty and people pushed to the breaking point and being shunned.
Some end up in care and live the rest of their lives with good caregivers. Some end up situations the humane society would not permit a dog to live in, terrorized in their childish mental condition until they lose their sanity, abused in every concievable manner.
Those who are not undergoing these situations, not personally responsible should not be making decisions for other people. Although we hate to admit with our desire for a happy ending, the strongest love isn't always enough to work these things out.