What if there were a version of "the pill" for men?
This theoretical pill (or maybe it actually exists in some form?) would make men 100% sterile, temporarily, while they were taking it, but they would revert a short time after they quit taking it.
What if the pill had one or more of the following side effects:
1. Reduced libido
2. Terrible acne
4. 1 out of X (choose a number) men became permanently sterile
5. potential weight gain (added for @syz) :)