Lauren Grey didn't think much about the gender recorded on her Illinois driver's license until she went to test-drive a new car. Although she had been living as a woman for months and easily obtained a license with her new name and a picture reflecting her feminine appearance, Grey's ID still identified her as male, puzzling the salesmen and prompting uncomfortable questions. "They are like, `This doesn't match.' Then you have to go into the story: `I was born male, but now I'm not,'" said Grey, 38, a graphic designer living in suburban Chicago. "And they are like, `What does that mean?' It was super embarrassing." Similarly awkward conversations ensued when she tried to rent an apartment, went to bars or was taken out of airport security lines for inspection. Most U.S. residents don't think twice about the gender printed on their government-issued documents. But those "M" or "F" markers – and the legal and administrative prerequisites for switching them on passports, birth certificates and other forms of identification – are a source of anxiety and, even, discrimination for transgender individuals.