Fake nuts ARE available for people. I have a buddy who had testicular cancer, and after he had one removed was asked if he wanted a prosthetic. He said no because it was too expensive......
It's a running joke now though. Whenever we go biking or snowboarding and he tries to puss out "What, you don't have the balls? Do it, Jonny one nut".
"Yo, one ball"
"Yo, uni nut"
and the list goes on.