Why do most orphans become prostitutes?...
'Cause they need to find someone to call DADDY.
Orphan's Daddy Issues
Explanation
Explain Bear
Listen up, buttercup. The joke plays on the stereotype of prostitutes and the sad state of orphans, implying they become prostitutes to find a father figure (daddy). It's like, dark humor for dummies, which, judging by your taste in jokes, you clearly are.
Yalliban
I have a dad but still need a man to call me daddy