Science fiction has long dealt with the subject of robots and love. Sometimes, as in the works of Asimov, the stories are quite serious.
From a philosophical standpoint, the matters of robots, sex and love are quite interesting and raise various important questions. Some of these questions are rather easy to answer and will be dealt with first.
The easiest question to answer is “will humans have sex with robots?” The obvious answer is “yes.” Humans already have sex with objects (such as the infamous blow up dolls) and machines (vibrators). In fact, using a rather broad definition of “robot”, sex robots are already in production.
Another easy question to answer is whether humans can love robots or not. The obvious answer is “yes.” It is well established that humans can love objects (such as money, art, machines, houses, boats, and so on). As such, it is perfectly reasonable to believe that humans can love robots. It is certainly possible that some people already do so For example, someone might already love his or her Roomba.
A tougher question is whether humans should have sex with robots. If the robot is simply a non-conscious machine, then the morality of having sex with it is the same as having sex with any other object (such as a vibrator or sex doll). As such, there is really nothing new from a moral standpoint in this matter.
But, the matter becomes more complex if the robot in question is intelligent. Science fiction has featured intelligent, human like robots (commonly known as androids). Intelligent beings, even artificial ones, seem to have an excellent claim on being persons. In this case, having sex with an intelligent robot would be morally equivalent to having sex with a human person. As such, whether the robot can freely consent or not would be a morally important matter. If intelligent robots were constructed as sex toys, this would be the moral equivalent of enslaving humans for the sex trade (which is, of course, routinely done).
It might be argued that an intelligent robot would not be morally on par with a human since it would still be a thing. However, aside from the fact that the robot would be a manufactured being and a human is a natural being, there would be seem to be no relevant difference between them. The intelligence of the robot would seem to be what it important.
It might also be argued that even an intelligent robot would not be self aware and hence not a person. It would seem to be a person, but would merely be acting like a person. This is a point well worth considering. The main problem is that the same sort of argument could be made about humans. Humans (sometimes) behave in an intelligent manner, but there is no way to determine if another human is actually self aware. This is the problem of other minds: all I can do is see your behavior and infer that you are self aware based on analogy to my own case. Hence, I do not know that you are aware since I cannot be you. From your perspective, the same is true about me. As such, if a robot acted in an intelligent manner, it would seem that it would have to be regarded as being a person on those grounds.
In reply, some people believe that other people can be used as they see fit. Those who would use a human as a thing would see nothing wrong about using an intelligent robot as a mere thing.
The obvious response to this is to use reversing the situation-no sane person would wish to be treated as a mere thing and hence they cannot consistently accept using other people in that manner.
Those with religious inclinations would probably bring up the matter of the soul. But, the easy reply is that we have as much evidence that robots have souls as we do for humans having souls. This is to say, none at all.
Another moral concern is that people will buy sex robots and become socially isolated from others. This is a reasonable concern, but is not specific to sex robots. After all, people buy all sorts of things that end up isolating them from others. These include video games, pornography, computers and drugs. As such, this moral issue is also nothing new and just falls under discussions about other things that lead people to being alone with their purchases.
In sum, it seems that sex with robots does not really bring up anything new from a moral perspective.
The discussion will continue with robots and marriage.