You are the gender you moved to. So, if you are a man who wanted to be a woman, and you got the bits and pieces cut off, and had the hormones to grow boobs, you are now a woman.
There is no one way to be a trans* man, but most trans* men were assigned female at birth. That does not mean that a trans* man is automatically female, however. They could have gotten sex-reassignment surgery, be intersex, or have been improperly assigned female at birth. There are other possibilities as well. Think beyond the binary.
Sex and gender are basically the same thing, so a trans man is male.
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since pretty much nobody on these forums knows what the hell they're talking about when it comes to trans people,
here are some links so y'all can start educating yourself:
[url=http://tranarchism.com/trans-basics/]Trans Basics[/url]
[url=http://tranarchism.com/2010/11/26/not-your-moms-trans-101/]Not Your Mom's Trans 101[/url] - while not a perfect "Trans 101" imo, it's far better than most.
[url=http://www.dyssonance.com/wp-content/uploads/2013/08/Introduction-to-Transness.pdf]Introduction to Transness.pdf[/url] - "A brief overview of the history and significant concepts applicable to the development and understanding of a Transcentric approach to the dignity, civil rights, and human rights of Trans people."