> If I could spare my future children from MS, schizophrenia, Downs, Huntington's, Alzheimer's, etc., I'd do it in a heartbeat.

I'm sure any reasonable person would agree; the more poignant question is whether you are sparing your future children or destroying some future children in favor of others. The former is something I hope any reasonable person would agree with; the latter is tantamount to eugenics.