In a story I’m writing now, the main character is a robot called Primitive James. Despite his male name, James is neither male nor female. James’ only interest in human sexuality is its relevance to solving problems; how it motivates behavior for example, or what rate of human reproduction is needed to sustain a population. And so forth.
To paraphrase Isaac Asimov, James has no interest in human seduction.
Unlike many fictional robots and artificial intelligences, James is not fascinated by or inclined to experiment with human reproductive imperatives or the emotional/social constructs that have built up around it over time. James does not yearn for the intimacy of sexual intercourse any more than you might yearn for the intimacy of having your timing belt changed.
It is decidedly human, this tendency to assign gender to inanimate objects. Perhaps it’s because sex, so essential to our collective continuance, is deeply embedded in how we interpret the world. Confronted with a bipedal creature such as James, who has evolved a personality that is in many ways indistinguishable from a human personality, it would take a conscious effort of will not to associate the robot with a gender. Indeed, Primitive James’ enemies routinely make a point of referring to the robot using the pronoun ‘it’ as a means of reinforcing James’ non-human nature in an attempt to depersonalize him and make him less sympathetic.
In the movie I, Robot, Dr. Susan Calvin, describing her work with US Robotics says:
"My general fields are advanced robotics and psychiatry. Although, I specialize in hardware-to-wetware interfaces in an effort to advance U.S.R.'s robotic anthropomorphization program".Rendered it in a more human-friendly manner, she "[makes] the robots seem more human." Science Fiction writers do the same. Robots in Science Fiction have been routinely assigned gender by their literary creators since the genre’s earliest days. In most cases this is intended to make the robot appear more human and be therefore compelling to a human audience, or to underscore some human aspect of the underpinning plot.
As a result, we have the iconic False Maria from Fritz Lang’s Metropolis, with her profoundly Art-Deco enhanced female appearance. Star Trek's Lt. Commander Data is not only male in appearance, but is 'fully functional' sexually and takes a periodic interest in exploring that aspect of his design. The robot Diktor, from Jean-Claude Forest’s Barbarella comic strip is fully functional as well, but worries that his technique is too 'mechanical'.
In general, the more inimical the robot, the less likely it is that gender will factor into its character.
Doctor Who's Daleks are as bereft of gender as they are of compassion. In The Day the Earth Stood Still, based on Harry Bates' Farewell to the Master, the robot Gort, which has the power to destroy humanity, is roughly human in shape. But Gort is otherwise without gender or expression, making its presence distant and foreboding. HAL 9000 from both the novel and movie versions of 2001 a Space Odyssey is an interesting balancing act. HAL is male, but only by dint of his disembodied voice. Otherwise his sole outward manifestation is the famous red camera eye. His voice, quiet and rational even while doing murder, provide HAL a disconcerting 'almost human' quality during the act. Yet it also serves to make HAL strangely sympathetic when his 'mind' is finally shut down by David Bowman.
Sex isn't important or necessary to Robots, but it is to the humans with whom they interact. Any number of writers have imagined the robot as not merely a helper or appliance, but as a life partner. From Helen O'Loy to Her, writers have explored the concept of robot/AI as the perfect mate; highly attuned to their human counterparts and utterly focused on the task of meeting their humans' emotional and physical needs. Human relationships, by contrast, are endlessly complex, with the wants, needs and egos of the involved humans frequently in competition, and self-interest complicating communication. Stories of humans entering relationships with machines literally designed to be their perfect companions are often couched as cautionary tales. However the persistence of the theme in movies and literature bears witness to its compelling nature.
Which of course brings up the question of whether it's moral have a relationship with a sentient (or at least seemingly sentient) machine that has no choice in the matter of whether or not it loves you. C.J. Cherry toyed with that concept somewhat in Cyteen, though it was not traditional robots in question, but genetically engineered and machine birthed humans whose conscious minds were programmed throughout their early lives and reprogrammable in adulthood.
A sexless robot welding cars, assisting in an office or cooking food is easy to think of as an appliance. It has no free will and that's OK - it's just a machine someone bought to perform a task. But assign the same robots gender and provide them characteristics we might associate with gender, and suddenly we see them differently; as more like us - more human. It's the way we're wired. It makes us more comfortable interacting with robots. And it's reasonable to speculate that future robots, programmed to optimize hardware-to-wetware interactions, are going to leverage that bit of human hard-wiring. Next thing you know you're wondering whether the android bar-tender with the sexy voice has a soul.
Happily for me, Primitive James seems no more interested in the human obsession with the soul than he is their obsession with sex.