Has anyone had sex in space yet?

Not that I have heard, although there have been some colonies of bees and bacteria that have probably had a very merry time in space.

As for humans, who would have the nerve to tell?

One thing is for certain, at least for hetrosexual unions, there have not been many opportunities.

There are some very interesting biological and even biomechanical questions raised by such research. I can't imagine anyone ever being funded to investigate any of them, however.