h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

In 1986 (?) I was in a biology class in school (doing heredity stuff) when a friend cracked the following joke: -

How do you sex a chromosone?
Pull its jeans down!

Finding this quite funny, I asked him where he got it from. He said that he had made it up on the spot. I told it to a few people in the following weeks and months but thought nothing more of it.

Some 3 years later I was watching a stand-up comedian on TV when he suddenly came out with the same joke! Hang on, I thought, where did he get that from?
Now my friend was and is a VERY honest man and a devout christian (albeit a bit cheeky!). He would be extremely unlikely to lie about the joke. It could be an honest mistake - he may have thought he made up the joke, having in fact heard it previously and forgotten. However, I told it to many people at the time who had never heard it before and have never seen it recorded before this date.

What I want to know is this - was I present at the birth of a joke?

(and did I help spread this new 'virus'?)


Have any of you had a similar experience?

Well, I was funny once, and I think I have invented some jokes when I was younger that has spread out. But not as far as to national TV though

It is quite possible that the joke spontaneously came into being in two different places....?

Yes, that's my point. Is this one that (a) was originated by my friend and spread to the planet (b) was repeated by my friend who was either lying about making it up or had forgotten he had heard it elsewhere (c) was made up by my friend and ALSO made up by someone else independently?

Will we ever know?