Which means in your mind, this goes beyond genetics and birth defects.

Yup. Nature and Nurture and flat out luck determine if you're going to be a saint or a serial killer.

You're proposing a government or some other agency decides who is and isn't fit to be parents,

Nope, but I know that's the only conceivable idea to put these things into practice. I can only control myself. I'm not going to produce biological children because I refuse to pass on my variety of messed up to the next generation. I can wish and wish for other people in similar situations to take the same considerations, adoption as one example and IVF and embryonic screening as another. Some will, some won't.

My ideal isn't a government agency saying 'Your SAT score was too low, you don't get to have kids, here's a sterilization pill.' it's people with inheritable conditions, or without the means to raise adults self-selecting out of being parents, or else taking measures to address the problems that can be fixed for the betterment of the human meta-animal.

I've examined this a lot. Do you think it's an easy or flippant thing to declare with the certainty that I do that I'm not fit to reproduce? If there was such an agency handing out chemical castrations I'd be the first one to sign up, and be glad for the privilege.