Artificial Intelligence (AI) can now accurately identify a person's sexual orientation by analyzing photos of their face, according to new research.

The Stanford University study, which is set to be published in the Journal of Personality and Social Psychology and was first reported in The Economist, found that machines had a far superior "gaydar" when compared to humans.

The machine intelligence tested in the research could correctly infer between gay and straight men 81 percent of the time, and 74 percent of the time for women. In contrast, human judges performed much worse than the sophisticated computer software, identifying the orientation of men 61 percent of the time and guessing correctly 54 percent of the time for women.

The research has prompted critics to question the possible use of this type of machine intelligence, both in terms of the ethics of facial-detection technology and whether it could be used to violate a person's privacy.

Michal Kosinski and Yilun Wang, the lead researchers of the study, suggested the software was able to find subtle differences in facial structure between gay and straight people and therefore could accurately conclude their sexual orientation.