I knew I forgot something--Ann Onymous reminded me--whenever I'm asked about a maiden name, I leave that blank.
There are weird little advantages to being FTM as opposed to MTF. Once I was applying for a census job, and there was a field for maiden name. We were all filling out the employment forms en masse, so I went over to the facilitator and said, "I changed my name years ago; should I put that in the 'maiden name' field?" And the woman said that I should only give what I was asked for and that I "obviously" didn't have a maiden name! So I didn't put down my old name.
Then again, I got a perfect score on their test and wasn't offered a job. But this was the last round of census jobs, and my application processing was delayed a few days because my Selective Service letter hadn't arrived yet. Those few days probably made the difference, but it's possible that my old name came up and I was rejected for that.
Anyway, I like that it's "obvious" that I would never have a maiden name. If I had been MTF, the facilitator might have asked whether I had ever been married, period, and that could have been awkward.