Kewcumber, there is absolutely no need to make the huge jump from privately disagreeing with the choice a couple made to state that somebody wishes everybody with a particular illness to be forcibly sterilised.
I disagree privately with people having children they cannot afford. I disagree with families above a certain size. That doesn't mean I think 'poor people should be sterilised' or 'women should be sterilised after their fourth baby.' It's a personal point of view and I object to the knee jerk and aggressive 'well if you think they shouldn't have children, you MUST think they should be forcibly sterilised.'
Rather, that in this case, other options should have been explored - as someone saliently wrote, the child has to live with the condition. It really is as simple as that. I also know, were I to be in this position, I would give serious thought to sperm or egg donation so that the 'faulty' (as it were) genes weren't used at all. However, that isn't for everybody and that is fine.