That's... complicated. There are multiple opinions about aborting fetuses that test positive for Down's syndrome. For one, the tests aren't always accurate. For two, people with Down's syndrome can live fulfilling lives, and have spoken out against the practice. But also it does place an additional burden on parents, and parenting well is already a hard job.

But I don't think it's a reasonable comparison -- autism has a much wider variability in how it expresses, from relatively benign (but still impactful) to fully incapable of self sufficiency.

I'd also argue just because we practice eugenics in case makes it ok to generalize to other cases (and furthermore, just because we practice it doesn't necessarily make it ok even in that case).