Looks like a team of computer scientists were able to make an algorithm that can guess a person's sexual orientation based on a photo of their face.
My first thought is that this is a little scary, but also that I'm not going to jump to any conclusions just yet since a 81% success rate for men and 75% success rate for women isn't great if they tested the algorithm on a sample population that represented a 95% straight, 5% gay split that is close to the real world's straight/gay population ratio. The AI would need to get above 95% accuracy otherwise it is isn't as accurate as an AI that simply always says the person in the photo is straight. However if they tested the algorithm on artificial population that had 50/50 straight/gay split then the results are really interesting. On one hand it proves it's not a choice, on the other hand it this could be a dangerous tool used for discrimination.
As worrying as this may be, I'm also fascinated and wonder how well the algorithm would work if they got a bunch of normal photos of people rather than ones those people selected to put on their dating profile. The features the algorithm tracks may simply be ones that the people posting those photos find attractive. I feel that the features gay people find attractive about their face would be different than the features straight people find attractive about their face. This would probably lead both groups to choose to post dating photos that exaggerate a different set of facial features.
In order to eliminate the possibility of the selection bias of their subjects, they need to get a large sample of photos of straight & openly gay* people that were not taken or chosen by the persons in the photos. It would be even better if they could make the people in the photos be as similar as possible when it comes to personal style, so the algorithm's results won't be influenced by their styling choices. Getting a large enough sample that fit this criteria would be extremely hard, because while I'm sure there are large databases of photos that fit this criteria (like a photo database of military recruits) those photos are not logged with the subject's sexual orientation and using them would also be violating the privacy of the people in the photos.
*I also secretly wonder how many of the straight people lied about being straight in their dating profile and what effect this has on the results.