Dr. Davidson grew up in Montreal, Quebec, and attended McGill University for his B.S. and later, his M.D. in 1980.
After an Internal Medicine Internship at McGill's Royal Victoria Hospital, he practiced general and emergency medicine in Newport, Vermont.
He went on to Internal Medicine residency at Stanford University Medical Center and then practiced in an HIV-related practice with Dr. Marcus Conant in San Francisco.
Next, he returned to Stanford for a postdoctoral fellowship in Allergy, Immunology & Rheumatology, which he completed in 1991 just before starting private practice in San Francisco, affiliated with California Pacific Medical Center.
Dr. Davidson is a Clinical Professor at U.C.S.F. and was an attending physician at the Stanford Allergy Clinic until that division closed in 1999.