The adult sex toy industry is booming, according to The National Turk, who recently reported the Ningbo Yamei plastic toy factory in China sold more than 50,000 adult sex dolls in 2011.

But now, futurologists are predicting even further developments in the field of non-sentient sexual playmates, as a report published in the May issue of journal Futures suggests that by 2050, red light districts could be filled with "android prostitutes".

Presenting an alternative future for sex tourism, the paper points out that - on the plus side - sex robots would be clean of sexual transmitted infections (STIs), not smuggled in from Eastern Europe and forced into slavery, and their work could be directly controlled by the local authorities.

SEE ALSO The Sex Doll Factory - Inside China's Plastic Fantastic Headquarters (PICTURES)

"The city council will have direct control over android sex workers controlling prices, hours of operations and sexual services," states the study.

Authors of Robots, men and sex tourism, Michelle Mars and tourism professor Ian Yeoman, both of the Victoria University of Wellington in New Zealand, said to Live Science.com: "It is feasible. Society has had relationships with machines and we continue to have increasingly intimate relationships with more and more sophisticated technologies."

And if the city council are in charge of the service, this will surely lead to stiffer competition in local elections (Click here for PICTURES of Boris Johnson Looking Silly).

The Huffington Post also recently reported on Bob and Lizzie (see VIDEO below), a British couple from Madley, Herefordshire, who have the world's largest collection of sex dolls.

The couple has more than 240 life-sized dolls, but unlike most people, they don't use them for sexual pleasure. They simply live with the dolls: have tea, eat supper, hang out.