Ah, I'm gonna get shot down BUT scientifically it is defying Darwins Survival of the Fittest by enabling couples who may not have been able to have children to have children.

NOT that thats a bad thing BTW, because we are defying survival of the fittest ourselves PMSL.

But I think thats the theory.

I don't agree its creating 'flawed' children, or anything like that, and I think anyone who does is grossly misinformed but the theory behind their argument is somewhat valid.