Education is the first part, as rd95 talks about. The more educated a populace, the lower the birthrate in general, which helps. But 'education' means more than basic K-12 stuff, it includes sex education, and not abstinence based sex ed either, but actual science based lessons on how human reproduction works and how to avoid conception. And that's unfortunately controversial.

Soon, genetic testing will be cheap enough that large-scale genetic analysis of the general population will be possible, and more people will know what kind of risks they undertake when they choose to get pregnant.

But I don't know how to change someones mind about having a baby if they are likely to produce a sick one. Typically, people don't decide to have kids, they just sort of happen. I'd like to see more people make the choice I have, and consciously decide to not pass on identified pathological genes. I don't know what arguments would persuade someone who had consciously decided to have kids anyway, knowing they could make them lethally ill.