I don't quite understand it.
Is it because people think they would be too "difficult to raise"? (in comparison to children without disabilities)
But well... I guess some disabilities make children not live very long. (I had a relative, who had spina bifida, who got more and more paralyzed until she died only 9 months old. But I am aware that not all people with spina bifida die that young)
I know that some people would refuse to have autistic children or children with Down syndrome.
And I have heard that some parents of autistic children want to "cure" them... (there is actually no cure)
Well... even though I don't want any children at all (because I probably would suck as a parent), I think that if I had a child, I wouldn't care whether it had a disability or not. I would love that child no matter what and also try to be a good parent as possible.
Maybe learn sign language, if my child was deaf. (even though I know a bit of sign language)