Hmm I see your view point.
I want 4 children (y'know but things change over time) not because I want to carry on my genetic train or whatever, but because I come from a big family. We have adopted people in my family too, and due to this condition I *might* have, I might not be able to have kids the natural way anyway. So what I can't have, means that I want it more.
However, limiting children to 1 child or 2 if both parents of the first child, were only children, is what China have done. I studied about that in geography, and yeah, I wouldn't say this policy should become enforced where I live..
But I understand about the whole adoption thing. It might be something I will have to end up doing anyway, so I get that totally.