> Are you a physician?

This sentence spoken on an engineering forum is pure... idiocy. Physicians are nothing more than bio-engineers, and if you apply sufficient reasoning you'll see that there is very little functional difference between the human body and a computer program (monadic equivalence)

FYI most physicians would find parent's advice agreeable. My physician said as much.

It doesn't take much reading about a topic as contentious as vitamin d supplements to come to similar conclusions. Have you done any review at all of the relevant literature?