Before I say anything, let me commend the OP and everyone who has posted so far. This is an extraordinarily difficult topic and I'm both proud of folks for being willing to tackle it and pleased that it is being tackled. The degree to which this happens (and humans being humans it would be remarkable if it never happened) is a question I have wanted to take on in writing for a few years now. I first wondered about this a litle more than a decade ago.
I have an ex, D, who I am still very good friends with. At the time, D was seeing this transguy named J. One day, D told me that she was thinking about transitioning. This caught me a little bit by surprise but I wasn't going to tell someone what their process was. I asked her some questions because, quite honestly, I know D well and I just couldn't see it. I asked her what made her think that she might be male and the only thing she could really come up with was that all of the musicians she loved and admired were men--D was and still is a big music geek. At the time, she wanted to be in a band. I suggested that perhaps she might want to give it some thought and that if she was really trans that would be still be there. Then I said I'd support her whatever she did. A few weeks later she was talking about having her first shot of T. Her boyfriend had a line on T through a backchannel. I told her that this seemed an extraordinarily bad idea.
Now, at the time both D and J were going to a trans support group and I wondered to what degree there was some transman being, well, an elder who might be able and willing to say to D, 'let's talk about this'. It didn't happen. Eventually D came to her senses and stopped transitioning before she did something permanent.
This incident has haunted me for a long time because I wondered how many times something like this was being played out and whether we, as a community, had the tools to talk about this topic in an adult and loving manner. So seeing this makes me feel good that the discussion can happen.
On another personal note, the book I've been afraid to write deals with this very question. I'm afraid to write it because, well, I know our people and I know how we can be--sometimes even asking the question "are there really that many more transmen around or is there something else going on" can cause a category five shit storm to erupt into one's life. But of the books that are scattered on my computer half written or mapped out in my head, the one on this question is the one that is burning a hole in my head, demanding to be written. Don't worry, I’m not gathering information or doing research.
I don't have any advice for anyone, although I will say these two things:
1) As Keri said, transitioning is the hardest thing you will ever do. I have often said that next to transition, everything else I will ever do fades into the merely difficult.
2) The only reason to transition is because you feel that something is just a bit off-kilter between body and brain. It won't make your life easier (see 1 above) nor will it fix your quirks and eccentricities. It solves one thing that is out of balance in your life and nothing else. Now, if it solves that problem for you, however, it will change your life and make it a better more comfortable place than you might have imagined possible. And if it doesn't break you along the way, the person who comes out on the other side will be a force of nature. You will know yourself much better and you'll know *precisely* what you are capable of.
Cheers
Aj