Announce on your university website that any student who self identifies as a creationist can not get a recommendation from you no matter the grade they got in your class.
Or better yet announce on your website that creationists can not go to med school.
What the hell, maybe its time to give the private sector a shot.
I've just told you that is not my policy.
As it happens, I doubt there would be a problem, but I'm certainly not going to carry out fool experiments to satisfy your curiosity.