[JediJones]

They have a mental problem, not a physical problem.

Or, they have a fetish for modifying their body. But no amount of modification can change your gender, which is defined at birth.

It is sexist to say that any man or woman has to think, feel or act a certain way. When a man “feels” like a woman, it means they’ve been programmed with a sexist notion of what a man should or can be. No thought or feeling is inappropriate for either gender to feel, therefore no feeling you have should give you any reason to think you need to “change” your gender with surgeries.

[FatherofFive]

They have a mental problem, not a physical problem.

Both.

[Tax-chick]

Great post, except for your using "gender" when you mean "sex." Our sex is male or female, defined at conception (except in the extremely rare genetic-damage cases that produce a mixture). Our "gender" is the pronoun we use, and an array of characteristics that our culture associates with males or females.

When a man “feels” like a woman, it means he has been programmed with a sexist notion of what a man should or can be.

That insight also works if you substitute "woman" for "man."