No sex or masturbating 24 hours prior. no std's. And they generally are trying to find good genes - so no family history of serious disease. Often a college degree is required as well.
You can actually get money for donating sperm, one should also note that you can not have intercourse 24 hours before you donate and you cant recently have done illicit substances.
They're going to screen you. You cannot have any STD's and you cannot have certain diseases that run in your close family. You will have to fill out forms noting things about yourself.
