A Friend of mine wants to know

All of the above

It's called a new category on redtube

Just gay sex. It's not you, it's a clone. And it's not your biological brother

Just gay. Clones are not technically related, they just have the same genetic code.

yes...

Are the clones XX or XY? Because one would be hot and the other would be hot for other people. (Joke)
But seriously if clones had the same genome then they couldn't reproduce. So who cares?
Now if we manipulated the genome(Going r34 here) then that would be something we should be concerned with.

None of the three. Because it's someone having sex with themselves. Since this is impossible without clones, we don't actually have a word for that.

We already cleared that - it's gaycesturbation

Selfcest? Maybe?

It's the unholy union of all three.

*Insert Ten/Tentoo joke here*

It's incest. Twins are technically clones (if they come from the same egg)