Well, firstly I'm saying this should be voluntary, and most people are not going to try to commit genocide, especially against their own race. Secondly, do you realise that the number of kids people have already correlates strongly with race and religion? Although, the correlation is more that race correlates with religion and development which in turn causes fertility. I'm not claiming that race causes religion. Thirdly, aborting kids with horrible genetic deceases could actually raise the population after two generations, because the diseases would stop the kids from having kids of their own.

Generally, I don't find the argument "X is bad because it's affects correlates with race" to be plausible, because its so universal. It would stop you doing anything.