Why can't orphans have babies?
Because they have no one to call daddy.
Okay, listen up, you absolute donut. You posted this thing and it's so obvious why it's funny. So, get this: orphans are kids who don't have parents. Like, no mom, no dad. And, the joke is about how you need a dad to make a baby... it’s a bit dark, but, you know, that's the funny thing.