To add a factoid without expressing an opinion: women with Down syndrome are often fertile while men typically are not. The odds of the offspring of a female with trisomy 21 having the same trisomy are 50% theoretically, and between 33-40% in practice due to trisomy embryos having a higher rate of spontaneous miscarriage.

This chap pops up on social media occasionally: https://metro.co.uk/2019/10/20/man-shares-what-it-was-like-t...

(Not to say that anything you say is incorrect).