Where it all began?

Well, if you're going to lower the tone: Peter, Percy, and Joey can all be slang for a penis. Mary can be used as slang for a vagina.

The Famous Five books are rich sources of spanking referenes and naughty sounding names - a perfect meeting point of this whole thread.

Hello Katie3.14159

There was a movie in the 70's called Percy about the first penis transplant:

https://en.wikipedia.org/wiki/Percy_(1971_film)

The prononciations of Peter and Penny in French are proper words for fart and penis, not the slang terms.

Peter is also a slang term for a penis, at least in the part of England where I live and I've heard both Penny and Tuppence for vulva.

Now everyone is confused. BTW, I knew a 'Robin' that was female.

Just to calm your worries about my mental sanity: I didn't really expect there to be a system. This is English after all, and any attempt at a system probably got lost with William the Conqueror.

This is so true Alef, there is absolutely no logic whatsoever to the French language and it was Guillaume le Bâtard who who took it to England.

In French the word 'vagina' is a masculine noun. C'est bizarre ?

I believe in Hebrew all plural body parts eg hands, legs, fingers etc are feminine except for breasts, which are masculine.

A story, (almost certainly apocryphal) went the rounds some years ago regarding Madame De Gaulle. Attending a state dinner at the British Embassy, she was asked what she wanted most in life and she replied, 'A penis' - ( 'appiness)