At what age should a child not have his parents coming into the doctor's office with him?

Depends on situation. Legally the parents have the right to any medical information from a doctors visit until the kid becomes an adult.In practice,it is worthwhile to let the older kid begin to have private conversations with the doc.I notify the parents & have them sign permission for kids 12 and up to be seen alone. I use a nurse when a chaperon is needed.Kids can decide what to tell parents, with certain exceptions.
16, unless child. Wants parent there or child is globally, emotionally or mentally delayed. In which case, child may never be old enough to see the doctor alone. Some 13 - 16-year-olds are adamant about not having parents join them in the office. For instance if child has genital or gender issues, in which case parents need to speak to the dr. Both before or after leaving jack or jill alone with dr. Or dr. + nurse.