It's not for me, but I think it's respectable if you're not responsible for the kid's mother as well. One of the major the problems with getting involved with a single mother is that she's the head of the family, not you. That leaves you with all of the responsibility and none of the authority. Adopting an orphan pairs the responsibility with authority and avoids the issue. I'd never call a man in this situation a cuck if the kid's mother was out of the picture.