Waiting for the flames on this one...but...
Many things "determine" ones "gender".
Some say it is the DNA. That is it. XX=girl, XY=boys, XXY=abnormal. In fact, anything other than XX or XY is abnormal. It just is. That is why there is a baseline normal.
Some say it is how you feel. That is nice. Some say it is how you dress. Interesting. Both of these seem to play upon the idea of 'it is somehow how you PRESENT yourself to society' that matters. Hmm. I understand that as far as sexual preference goes however not when it comes to "being a man" or "being a woman", as if it were up to us what sex we are.
But saying, "I am now Chelsea" and expecting the world to suddenly forget that you have male DNA and fully developed genitalia, that is strange. He may feel, dress, try to 'act' like a woman, but isn't that where the saying, "a wolf in sheep's clothing" came from? Not that he is dangerous (ie a wolf) but that underneath the disguise he still is what he is, a man. Even if what he is isn't what he wants to be.
I wish him the best. And certainly hope that he is able to find freedom much sooner than they want him to.