They are yet to hit the shelves, but activists are already campaigning against the sale of so-called sex robots, which may be "harmful and contribute to inequalities in society."
Several companies are developing robots that can be used as sexual substitutes for humans, leading to the launch of the "Campaign against sex robots" on Tuesday to highlight the potential dangers.
Kathleen Richardson, a robot anthropologist and ethicist at De Montfort University in Leicester, U.K., is leading the campaign and warned that sex robots might come in the guise of children, as well as adult women.
"When I first started looking into the subject I thought, 'oh sex robots, that's harmless and perhaps these robots would reduce demand for real women and children,'" she told CNBC on Tuesday.
"But then as I researched the subject more I found that the opposite was true—that rather than reduce the objectification of women, children and also men and transgender people, these robots would contribute and reinforce their position in society (as objects)."
She added: "We have the real use of women and children in the real world (as sex objects) and this kind of paraphernalia reinforces that message."
Sex dolls are nothing new, but there is rising interest in robots that can be used for sexual purposes, with electronics and robotic companies hastily trying to get them to market.
For instance, Californian company RealDoll plans to sell an "artificially intelligent" rubber sex doll able to talk by 2017.
Then there's True Companion that has been designing what it claims is the world's first sex robot—called Roxxxy—for years. Male sex robots are also in development. Her price starts at $6,995.00 but approaches $75,000.00 for custom designs, the company told CNBC.
Roxxxy "knows your likes and dislikes, carries on a discussion and expresses her love to you and (can) be your loving friend. She can talk to you, listen to you and feel your touch. She can even have an orgasm," True Companion says on its website.
Asked whether sex robots like Roxxxy could have a detrimental effect on society, founder of True Companion and inventor or Roxxxy, Douglas Hines, defended his creation, telling CNBC that she has a useful role to play in society.
"Roxxxy provides physical and sexual pleasure but also provides social interaction and engagement," he said. "It's customizing technology to provide a perfect partner - she's not meant to replace a real partner but is meant as a supplement," he said.
He said the sex robot was a useful addition to society and could have therapeutic uses, such as sex therapy. He believed that, contrary to Dr Richardson's concerns, robots like Roxxxy help to reduce sex trafficking, sexual and domestic abuse. "As long as we're not hurting anyone, there's no problem with it," he said.
Hit to human relationships?
Erik Billing, an associate senior lecturer at the School of Informatics in Sweden, has also joined the "Campaign against sex robots." He told CNBC on Tuesday that he was worried about the as-yet unknown effect sex robots could have on human relationships.
"Already today we have many kinds of sex toys and applications for robots which are great but we're also beginning to see the introduction of sex robots. There are a lot of worries that we're introducing this technology on a large scale without looking at what consequences there are on human-to-human relationships," Billing told CNBC.
Billing said that sex robots were a part of a global trend towards greater isolation, with many people shopping from home or living alone, despite studies demonstrating the need for human contact.
"Introducing sex robots that could replace partners is the extreme of this trend, where we start to objectify our human relationships," he said.
Billing said widespread sale of robot sex toys was near.
"We're on the brink of these applications being sold in stores. In five to 10 years time this will be a common product in any random sex store."
—By CNBC's Holly Ellyatt, follow her on Twitter @HollyEllyatt.