Genitals as insults.

[Joe_the_Lion]

When were expletives for genitals first used as insults. And why?

Yes, they have a dirty connection insofar as associated with toilet doings, but have a sensual connection with pro-creation and sex. Why would somebody never call somebody a kidney or a liver??

I refer primarily to d!ck, c0ck and the awful c u next Tuesday.

[bigbus]

also ...Till We Av Tea joe

[Quizmonster]

D!ck as an insult is first recorded in the 1960s and the c-word only as far back as the 1920s, so both are relatively recent. I must confess, I have never heard the co-word used as an insult, but only as a friendly greeting-word along the lines of 'mate'...not inappropriate, I suppose.
Anyone who swears he was using the first of these in the 1940s should get in touch with the editors of The Oxford English Dictionary with suitable evidence!

[Quizmonster]

I should perhaps point out that spoken usage probably involved these obscenities long before they became common in writing. It may well be that the bosun aboard HMS Victory at Trafalgar was calling the sailors all the effing c's under the sun...we'll never know. Until phonographs and tape-recorders came along, there obviously was no authenticated record of ordinary speech. Thus, we have to rely on written records.
It was not until after the famous 'Not guilty' verdict at the end of the Lady Chatterley's Lover trial in 1960 that the flood-gates of written obscenity were thrown open. Prior to that, they were taboo. Hence, no doubt, the comparative recency of the dates I offered earlier.