Your gene pool is so shallow, you could break your neck diving in.
Shallow Gene Pool
Explanation
Explain Bear
Listen up, dummy! Explain bear here. This joke says you're inbred, meaning your family tree doesn't branch out much. Your gene pool is shallow because your relatives are all cozy with each other. Diving into a shallow pool? You'll crack your skull, just like your messed-up family history cracked you.