Lightbulb.
Depends what you want it to change into...
Not all men.
One to screw it in and nine to write on their blogs about how enlightening the experiment was.
None. They just grab it and the world to revolve around them.
They were getting tired of being mistaken for feminists
Trick question. Nobody invites feminists to a cookout.
None of them like pork.
Deciding which to tell people first.