My son has never had one.
I think I answered this on the other forum, they may have new guidelines to check for abuse, I would ask the doctor why the exam was done , he is bound to tell you ..
I uncovered a repressed memory of this happening to me at that age. My mom who is a general practitioner remembers it, but said it made her uncomfortable at the time and she did not know why it should be called for at that age.
I was hoping a pediatrician might chime in with any insights, as it still puzzles me to this day.
It might have been that some symptom you were having suggested an irregularity in that area, though I'm not clear why the doctor would have failed to discuss this with your mother if so.
They will do a rectal exam like that if a child is having GI issues. i had one when in elementary school as i was losing weight, had pain etc. (eventually found out that I had a duedanol or intenstinal ulcer). But otherwise, I don't think this is routine in any way. Don't know anyone whose kids have had such a thing done nor have mine. good luck
Best thing is to ask them why it was done .certainly with the 5 year old as it is recent ...