Hey, you may want to call your states EEO office. Some states will not allow an employer to do that, unless you are absent for 3 days or more.
I worked at a place that tried to do that, but they went too far. They said if you called in sick, you had to come in, then the manager would decide if you were too sick to work. That didn't last long, because when people said, "If I come in real sick, and the manager, who isn't a doctor, decides I am ok to work. Then I end up sick and in the hospital, I am going to sue" They backed off on that then.
Then when they were told that they can't require a doctors note unless someone was gone for 3 or more days, they backed off on that as well.
Check your states laws, and if they push it, make them read the law.
Or, I like this idea, go in sneeze on your hand, make sure it's nice and wet, handle a pen, pass it to your boss. Then add this nice touch, tell them that he has something in the corner of his eye(the eye is the best way to transmit sickness). I did this with the cop that gave me a ticket a couple years ago

(Except for the eye part).