NASA commander Alan Poindexter told reporters that sex and romance is banned in outerspace. The funny thing is, the whole article is about three women in space together, LOL. Are they worried about something between them?
I would think zero gravity would make it pretty difficult to assume position, but I'm sure astronauts are very, very smart people and know the ins and outs of outerspace muscle control.
Also, I'd hate to be on that mission to Mars. Man, that's a mighty long time not to have sex. I wonder whether they'd allow vibrators. Of course, if one is lost in outer-space, floating forever, I can't imagine what an alien would make of it when he finds it.