In most situations there is no legal requirement for a woman to be present when a male dr. examines a female patient, and when a female dr. examines a male patient there is also no legal requirement for a male to be present. Or anyone else to be present.
I have looked into this matter thoroughly in the US, and there is no insurance requirement either.
There are however local policies that individual doctors or practices may put in place for whatever reason. Often when they do they claim either a legal or insurance requirement makes them do so, but that is not true.
Personally I have had every variation that you can imagine, but the majority of the time I see a female doctor and there is no one else present, except to assist and that only happens occasionally.