But that begs the sci-fi question. If you could do it with clones, would you? This of course gets mucky quickly. I certainly don't know the answer to the nature-vs-nurture debate, and since we're talkin' sci-fi, I can't rule out that the clones wouldn't share the memories of the original. Even if I could be certain they don't, and they weren't raised together or think of each other as sisters, it'd still be far from ideal. You'd still have to worry that you'll get them confused and accidentally focus all your efforts on clone A, leaving poor clone B jealous or nonorgasmic. So sex with clones still has it's flaws.
Sex with your lover's time-traveling future selves, however, could sidestep that. It wouldn't matter if you gave a little to much attention to one version of your partner, as he or she would still have the pleasant memory of getting your full attention during the same "closed-circuit orgy". It's not like you get jealous of yourself whenever you have a mediocre orgasm.
I suspect, actually, that's why you've nevermet a time traveller. I'd guess that in the future someone invents atime-machine. Domesticating dinosaurs, killing hitler, retroactivelyimproving their own childhood, and striking it rich on the stock marketonly occupies his first couple weekends. Then, he realizes he couldgo back in time and seduce that failed first romance. Of course, thismakes him feel awful - he doesn't want to cheat on his wife. That'swhen he realizes the time machine can allow him to fulfill at least onesexual fantasy he'd previously written off - the threesome.
So,he approaches his wife and says "Honey, I've built a time machine and now we're rich. But I've never been to an orgy, because I only have eyes for you. But how about I have sex with you and your 30 minutes older self, ...and maybe your one hour older self? Hop in the timemachine, loop around a couple times, and we'll have fun, okay? I can fuck all of you, and you can make out with yourself, and you'll be so fucking hot! Please?"
His wife stands aghast for a second. There's something distinctly masturbatory about the notion of making out with her future self forher husband's edification, not that she's against masturbation, but she's not sure she wants to...
Then the eyeslight up. "I'm not the only one who can get in that time machine, dear. I want your cocks in every opening!" Next thing you know, there's as many of each of them as they can fit in the bedroom, fucking each other every which way, and possibly trying hard not to admit there's something just a touch gay about the whole scenario.
Eventually, they probably realize that used to be younger, hotter, and in better shape, so why not go back and get some of your own barely legal ass? And that's where the time machine fails them.
If your older, wrinklier, desperate horndog self showed up to make you their personalsex-slave, you'd be all "Fuck this! I ain't ever inventing that timemachine in the first place!" At which point your future horndog selfevaporates in a violent paradoxical time wave.
I suspect thisvery scenario is happening around us all the time. Hundreds, maybethousands of would-be scientists are carrying the deep dark secret that they were nearly gang-raped by their future selves who thendisintigrated before their eyes. That'd turn anyone into a neo-luddite.Hell, for all you know, I might have been up in arms about the LHC because my erection-laden future self used it to attack me.
I think I'm going to start asking every non-scientist I know: "So, have you too given up your plans to build a time machine after your twisted pervert future self tried to rape you?"
No use asking those who actually are (still) scientists, after all, as those guys never get laid.
