At my 13 yr. old son's physical last week the Dr. said that my son's penis appeared twisted. The Dr. had noticed this at a previous physical, but apparently now my son's penis seems to be more noticeably twisted. What could cause this & should I be worried?

Well asking the doctor who said this would be the idea thing how and why and what effect will it have. Most likely it will be something that you will have a specialist double check.

Unfortunately, the day of my son's physical was the last day for his Dr. in that practice. She is leaving to return to Asia to practice there.