Absolutely it's about risk, but it is frustrating how little it's addressed. Having kids younger is better for the childs genetics. At least if you're trying to minimize mutations. Additionally, just because a kid comes out without down syndrome doesn't mean they don't still have genetic damage/mutations.
https://www.scientificamerican.com/article/older-parents-may-both-pass-down-more-new-mutations/
It's also important to note that the wall exists for men as well. Life is complicated and each persons path is different. I think we can all agree though that having a kid young helps your kids to avoid genetic mutations. There's more to just genes in raising a child though.