http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0036671
“Research has shown that people are able to judge sexual orientation from faces with above-chance accuracy, but little is known about how these judgments are formed. Here, we investigated the importance of well-established face processing mechanisms in such judgments: featural processing (e.g., an eye) and configural processing (e.g., spatial distance between eyes). “
Some people do have discernment. Nothing research wants to know about.