Apparently, I have straight hair.But gay hands.Specifically, it seems that a counterclockwise hair whorl is more prevalent in gay men than would be expected. And the finger length ratio in straight men is that the index finger is shorter than the ring finger, whereas often in gay men it's equal in length or longer (the same as with straight women).
There's an interesting article in New York magazine about the science of gaydar. There are some discernible traits that are more prevalent in gays and lesbians that speak to the biological roots of being third (or fourth) sex. I'm not fixated on the whys and wherefores of being homo, but it's worth a read.