Tried to get a beautiful son on Extinction (yes, through cheats), here's how it went:

I beat up the reaper queen a good bit, till she started smelling, then after about 1 minute of just glaring at her, SHE TOOK A DIRE BEAR AND IMPREGNATED IT!! I was shocked, I couldn't believe she'd rather have a bear as a the father of her new child. Anyway, tried again, she finally chose me as the wonderful father. I killed a bunch of gigas like they were dodos, and eventually I was ready to birth my beautiful son.

I got to the little trap thing I made, AND HE FLEW OFF THE SIDE OF THE WALL AND OUT OF THE CAGE, then I died of hunger, ran back over, and HE WAS IN ONE OF THE BUILDINGS!!!

After a while, I managed to claim him, his name is Stinker