So, although I suppose there is some scientific verification for identifying gay men by their face besides the ever-present Lance Bass (who sometimes looks like a lesbian)
and I myself have considered, in an off-handed kind of way, that "gay face" is evident in some sort of ratio between chin and cheekbones, I think I know now why there has always been something "off" about 50 cent for me--his gay face.
I noticed it most recently in his video "Have a Baby By Me, Be a Millionaire." I don't know if it's his long eye-lashes, the recent Price-era facial hair he dons in the video, his utter lack of chemistry with Kelly Rowland (ostensibly his real life girlfriend, although who knows some people can't act), his lack of delivery on his tracks about his sexual prowess, or the rumors of his attendance of certain New York gay-sex parties but he seems to me to be a fitting example of "gay face." The video itself has a strange disconnect between 50 Cent's self imagining as a great lover/father/romancer and the chorus which discloses massive payment for producing proof of his viable heteronormativity to the lady in question.
That said, searches for the biological bases of homosexuality and it's identifiable traits scare the fuck out of me ("Biological, Don't Bother," as Shaquille O'Neil once rhymed).