Are transgender people born that way, or do they become that later?

Answer by Caroline Collins:

Transgender people, like gay/bi/pan/etc. people, are born with their characteristics encoded into their psyche. The only reason it may seem like a choice is because, at least in the case of LGB people, it is usually in the process of sexual maturity that this self-discovery occurs. While transgender people can express themselves much younger, it may be disregarded as child’s play, or it may merely turn out to be transvestism.
The most important thing you can do when you suspect that a person has a certain characteristic is ask them about it. If they are comfortable, they can explain themselves to you better than anybody else.
Are transgender people born that way, or do they become that later?