Yeah.. it's weird. I work with an adult fellow with what I assume is a similar I/DD and when his parents come around it's always "rockstar" and "wildman" and stuff like that.. I would never film it or post it on YT if I were the parents though; that's just entering a world you don't want to enter.
It's a developmental disorder, often caused by alcohol. Getting drunk and having sex is pretty common but often people don't know they're pregnant and continue to drink like normal several weeks into their pregnancy, which can lead to things like Microcephaly. That doesn't mean that's the only cause by any means, but it's one that's overlooked.