It happened like this:
https://twitter.com/#!/hanneblank/status/141997572339408896 Sperm free, your jimmy needs no hat
Because we now know that
You're sperm free for life
'Cause of irradiation
or genetic mutation
You now are sperm free
Your vas deferens truncation
Caused your girlfriend elation
For you now are sperm free
All of your fornication
Won't increase population
Now that you are sperm free