I think the difference is between children with disabilities that are already here versus knowingly having a child that will have a disability. Children with disabilities can live productive lives and be happy. I don't think any of us are against children with disabilities. However, I think it is unfair to have a child when you know it could be born with a disability, just because the parent "wants" a child. There are many children already born, healthy and otherwise, that need loving parents. Yes there are many things that can happen in life to make a child's life hard but why knowingly add to that. (obviously it is a different case if the parents had no idea they were carriers of a disease or disability)