Electroplankton calls our attention to this article. Although it seems the existence of a "gay gene" is still contested, some researchers have found some biometrics that do seem to correspond with an individual being gay. For example, if a male's hair swirls counterclockwise (as mine does) and his index finger is longer than his ring finger (as mine is), if he's left-handed (I'm not), or if he has narrow fingerprint ridges (I don't think so) then there's a possibility that he's gay (true, but you already knew that.)

This is surely good news for the gaydar-impaired (such as myself) but this study also raises the same troubling possibility that the facial pattern matching widget did. Data can be mined for evil as well as good.

Although it would be difficult to get people to enter "hair swirl direction" and "finger length ratio" into their (say) DMV forms, it wouldn't be difficult to take their prints or determine which hand they used to sign the form. And while this data wouldn't be conclusive, it could raise a pink flag. This might not be that useful to an organization that precisely targets individuals. But to an organization that's after a population, especially if it doesn't matter that a few fish escape the net, it might be useful indeed.