Forum Making sure registered users are physicians
 

I am setting up a medical forum and want to include both physicians and non-physicians. Because of the sensitivity of patient information, some forums would be closed to non-physicians. I visited another similar forum based in England. At registration, the applicant had to provide their British medical license number to prove that they were doctors. In the US, each state issues its own unique medical license number whose formatting varies from state to state. The one positive for state medical license numbers is that they are public info and can be verified. DEA numbers are national but are not public information and therefore cannot be verified. Ideally, I would like a question to be answered at the registration process that would confirm that a valid medical license was being entered. Seems daunting...any thoughts?
Thx
Rick