Genetic Dead End 

A homosexual who will not pass on his genetics to his offspring. Coined by Stephen Colbert, literally means a dead end for your family's genetics.

"Tyler told me he was gay; wait until his parents find out he's a genetic dead end.

Genetic Dead End by ToasterBoy15 July 3, 2011

Dead end genetics 

When a person has facial features so ugly, that nobody will have sex with them. Therefore, putting a dead end on their family tree.

Person 1: The reason why Katie won't go out with me is because of my ugly ass face!
Person 2: I think that's called "dead end genetics".

Dead end genetics by Ironic depression January 26, 2017