Because
it's from the Greek - poinē - meaning punishment, whereas penis is from the Latin pēnis, originally meaning a tail. According to my copy of Chambers, anyway.

Generally if you think the English language is sexist you don't know enough about its etymology, and are in danger of thinking that the word "history" should be spelled "herstory" when talking about a woman.

From the Greek histōr, meaning knowing.
( Legionary - My god, Brian, there's a message in my alphabets, Mon 4 Jan 2010, 15:52, 1 reply)

Pah, you can prove anything with facts...
:-)
(MrOli is ugly, but in the morning you will be sober, Mon 4 Jan 2010, 15:59, closed)

Indeed.
Sorry, just re-read the above and it sounds a bit condescending - you just managed to hit one of my pedant buttons :)
( Legionary - My god, Brian, there's a message in my alphabets, Mon 4 Jan 2010, 16:01, closed)

S'all good :-)
My tongue was very firmly in my cheek. Almost responded with a mini-rant about all the feminists wanting to miss-correct (if that's a word) occurances of "man" with "woman", but haven't really got the brainpower left this late on the worst-of-all-Mondays...
(MrOli is ugly, but in the morning you will be sober, Mon 4 Jan 2010, 16:37, closed)