Under the law, the difference between an act of sex and an act of assault hinges on one idea: consent. If a person agrees to have sex with you, you're having sex. If they don't agree, or actively disagree, it's a crime. Obviously there are gray areas, and that's why rape trials exist - in the best cases, such trials are intended to determine whether consent was given.

But what about robots? Do you think the blondie bot in Cherry 2000 was really capable of giving consent to have sex with her human boyfriend? Or did her programming simply force her to always have sex, whether she wanted to or not? And what about the Romeo Droid in Circuitry Man, or the Sex Mecha in AI, who live entirely to sexually please women, even when those women are abusing them or putting them in danger?

Then there's the opposite problem, which Ekaterina Sedia tackles in her recent novel Alchemy of Stone. Her main character is a robot whose creator built her without genitals. Even when she wants to have sex, her body makes it impossible for her to consent in a recognizable way (though she does manage to figure out a technical workaround).

Whether programmed to have sex, or designed to refuse it, the problem these fictional bots face is a lack of control over their own desires. You can't really be said to consent to sex if you're never given the option to choose between "yes" and "no."

Cat Rambo has written a short story where one of the characters is a female superhero whose mad scientist creators made her hyper-sexual. No matter what happens, she's always aroused, regardless of whether she wants to be or not. Her solution to this design feature is never to have sex with anyone. She doesn't like the idea of being trapped inside a sexual desire that a bunch of men designed into her without consent.

Researcher David Levy got a lot of media attention for his recent book Love and Sex with Robots, where he argues that by 2050, people won't just be having sex with bots - they'll be falling in love with them, and even marrying them. He talks about the development of emotional and social robots, creatures programmed to perceive and imitate human emotions. Already, roboticists at MIT have created several models of bot that respond to facial expressions and tone of voice with so-called appropriate emotions: An angry voice makes the bot cower; a smile returns a smile.

But of course these emotional robots have been programmed with what somebody thinks is an appropriate response - sort of the way Rambo's superhero has been programmed to respond to everything with sexual arousal. If we accept that robots will achieve human-like intelligence, it seems likely that such bots will sense a difference between what their programming makes them do and what they actually want to do.

So if a robot has been programmed to respond to human sexual arousal with more sexual arousal of its own, is he actually consenting? Or is he just going through the motions of pleasure and desire, wishing that he could control his own responses enough to choose whom he had sex with, and when?

Questions like these, raised in science fiction or speculative science writing like Levy's, are inevitably really questions about ourselves. As of yet, we have no bots who are sophisticated enough to experience intimate relationships with humans - by programming, or by choice. But as humans, we often exist in the gray areas of consent when it comes to sex. Our physical desires, our basic sexual programming, may conflict with what we actually want to do.

Certainly there are many situations where it is obvious that consent has not been given, or has been. But for all the situations in the middle, we are like the bots we imagine that one day we will fall in love with. We cannot untangle what we think we should do (our social programming) from what we want to do. Or we can't disengage our raging physical urges (more programming) long enough to ask, "Wait, do I really want to have sex with this person? Or do I just want to have sex with anything, including furniture?" In Charles Stross' excellent novel Children of Saturn, the always-randy sexbot heroine knows the answer to this question, and responds by humping hotel rooms and spaceships.

So will you ever be able to have consensual sex with a robot? Maybe. Sometimes. Unless you aren't bothered by having sex with a slave or a brainwashed victim, having relationships with robots will probably be just as complicated as having them with humans.

This is the first in a series of columns called Fully Functional that I'll be writing about science fiction and sex. If there are any topics you want me to tackle, pipe up in comments. Nothing is too weird for me. Really. Nothing.

I'm Not Feeling Myself Tonight (1975). One of those bizarre Britsploitation films that could only have come from the groovy 70s. Barry Andrews is a virgin who goes to work in a weird sex research institute, where patients run around naked and everybody does nude aerobics. But Andrews still can't seduce the hot secretary — until he invents a machine (nicknamed Agnes for some reason) which puts out a "sonic aphrodisiac" which turns anyone into a sex maniac. Andrews doesn't quite manage to seduce Cheryl the secretary, but does have fun using Agnes on his overbearing boss, and a pesky woman who's campaigning for moral decency.

Randy The Electric Lady (1978). Desiree Cousteau plays Randy, who's having a hard time reaching climax — until she goes to a weird sex clinic, where she manages to climax so hard, she explodes all their computers and measuring instruments. Then the researchers realize that Randy secretes a special substance called Orgasmine when she climaxes, and everybody who's exposed to Orgasmine turns into an easily controlled sex rabbit. Of course, being a mad sex doctor, the head researcher Dr. Harrison wants to use Orgasmine to RULE THE WORLD! Bwa ha ha ha....

The Ultimate Attraction (1998). The source of the clip featured above. Written by scifi pornmaster Rolfe Kanefsky, Ultimate is loosely (and I stress "loosely") based on the classic comic Click by Milo Manara. But whereas in Manara's comic, a woman has a brain implant that cranks up her sex drive at the twist of a dial, Kanefsky's version is a directional beam that affects anyone you point it at. And somehow, in the course of Ultimate's storyline about a troubled mom-and-pop gym that finds a sex-ray, the device gets changed so that any electrical device can turn into a horniness inducer. Like the boombox in this clip, where a bodybuilder's walkman runs out of batteries:

Flesh Gordon (1974). The Emperor Wang is using a "sex ray" to turn everyone on Earth into uncontrollable sex maniacs. So it's up to Flesh and his friends to stop him. At least it's better than the awful sequel, in which a supervillain tries to use an "impotence ray" to rob Earth of all its virility. Ugh.

Flash Gordon (1980). Weirdly enough, both Gordon films feature the villain using technology to make people into sex-fiends. In Flash, Ming uses his weird power ring to hypnotize Dale Arden into performing a sexy dance for him.

Shivers (1975). David Cronenberg's third film includes much of the "body horror" for which he became famous. A parasite which scientists developed to replace damaged or diseased organs goes out of control and starts turning men and women into sexual predators. The host can only spread by having its victims sexually overwhelm other people, and a new self-contained tower building becomes a perfect breeding ground. There are lots of bloody scenes of mangled faces, and then it ends up with the world's most disturbing pool party:

Torchwood, "Day One" Trust crazy Doctor Who spinoff Torchwood to go way, way over the top when it comes to alien sex-parasites. A purpley gas takes over Carys, a lovelorn woman, and turns her into a hot sexpot who goes around seducing men... and then reducing them to a little powder when they orgasm. She seems to have the power to sex-craze other people too, since she's able to get the straight (as far as we know) Gwen into a hot snog-a-thon. Here's her best moment:

The Curious Dr. Humpp (1966). We've already sung the praises of this bizarre hybrid movie. Dr. Hummp needs to absorb the erotic energy from rabbiting nymphomaniacs to keep himself and his pet brain healthy, so he kidnaps nubile young people and keeps dosing them with powerful aphrodisiacs to keep them in the mood.

• Barbarella: This movie was all about sex, from the opening credits where Jane Fonda strips down in zero gravity, to her encounter with Dr. Durand Durand's sex organ called "The Excessive Machine." Which is basically a piano that plays with your genitalia. It's supposed to kill her, but of course Barbarella breaks it, oh my. She also has super-sci fi sex in pill form, which manages to curl her hair a bit. There's even a character named Dildano, in case you had any doubts about all the sex.

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• Demolition Man: This movie has a scene where Sylvester Stallone gets it on with Sandra Bullock's character through some high-tech sex helmets. You put them on and "think" about sex, so no bodily fluids are exchanged. That way you can do the nasty and stay "pure." Thankfully, it saves us from seeing them writhing around in bed together. A sad Stallone retires to his apartment to knit (no joke), but he gets a wrong number video phone call, so you can still see some boobies. He probably wrote that scene in himself.

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• Liquid Sky: In this 1982 cult-classic, fashion model Margaret has a troupe of tiny aliens following her around and sucking up the endorphins released by the people she has sex with, because that's where they get their fuel from. Must make finding a service station a bit rough. She has trouble hiding the ever-growing body count until the aliens help her out and start vaporizing them for her. Where else could you get a line like, "I bet you $300 I can fuck Margaret and not die!" spoken by a woman?

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• Battlestar Galactica: There's a lot of sex going on in this show, because apparently Cylons are equipped with a horny circuit that's been switched into overdrive. Except for that short, balding guy. We've never seen him try to do the deed. Plus, Cylon's spines glow red during sex, which you think would make detecting them a bit easier than the iffy blood-test solution that Baltar comes up with. Plus, Starbuck gets strapped down and has an ovary removed in a Cylon reproduction farm, which means they're just having sex for the fun of it.

  
  

• Moonraker: James Bond ventures into outer space, has slow-motion fights with laser beams and while wearing a spacesuit, manages to turn Jaws into a good guy, and also gets down with some zero gravity action with Dr. Holly Goodhead. The film's effects are pretty laughable at this point (the space shuttle has LASER BEAMS, for god's sake), but that sex scene made it all worth it when you were ten years old. Plus Q gets off a good one-liner at the end when the Prime Minister video calls Bond to congratulate him and they sex him and Dr. Goodhead floating naked under some silvery space sheets. M says, "What's he doing?!" And Q, staring at a flight path quips "I think he's attempting re-entry!" Zing.

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• Species: Scientists get a message from the stars in this film, and it sounds suspiciously like spam. "Free unlimited fuel now! Ask me how!" They follow the instructions, which involve splicing human DNA with alien DNA, and it gives birth to... Natasha Henstridge. She escapes into the wild with her supermodel good looks, and the fact that she changed her haircut. What a disguise. Even one of the scientists assigned to track her down doesn't recognize her, and they have sex. She's like Clark Kent with that damn hair. Anyhow, she's hot, struts around naked, and doesn't hesitate to kill people who get in her way.

  
  

• Demon Seed: This 1977 film featured a sentient computer named Proteus that also controlled every aspect of the house that his creator's wife lived in. As he begins to go HAL-style crazy, he tells the good doctor's wife that he just wants to have a child, and she agrees! There's some cyborg/robo sex going on, which has to be seen to be believed, including the robot's line "If you prick me, do I not leak?" If your house starts pleasing you sexually, it's either time to move, or to re-appraise your property.

• Sleeper: In this Woody Allen film, Allen mistakenly gets put into cryogenic freeze and wakes up 200 years in the future, where all men have been rendered impotent, except those of Italian descent. Orgasmatron booths are popular destinations, where instead of making a phone call you get off, and "intoxication orbs" are passed around at parties, which appear to make the holder experience sexual bliss. Sounds like a decent future to me, thank god my great-grandmother was Italian.

  

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