"Gender Identity Disorder" is extremely inaccurate as a term, in my opinion. It should be called Sex Identity Disorder. Gender is a social construct of how a person should abide with the "normal" roles of gender. How a person dresses or behaves does not influence his/her sex whatsoever. Since gender is entirely subjective, you cannot make it a "disorder."
SID (Sex Identity Disorder) is when you're born biologically a sex of what you perceive to be the opposite. Because you can NEVER dispute the biological fact - either you are born with a male or a female genitiala. If you have a penis and still say you're a girl, then you have SID. The same is true for women who think they got penises. There are RARE cases of intersexed babies but they do NOT have mental illness at all.
Homosexuality is NOT a mental illness and has been long removed from the DSM so you cannot compare homosexuality to BIID or SID.
SID (Sex Identity Disorder) is when you're born biologically a sex of what you perceive to be the opposite. Because you can NEVER dispute the biological fact - either you are born with a male or a female genitiala. If you have a penis and still say you're a girl, then you have SID. The same is true for women who think they got penises. There are RARE cases of intersexed babies but they do NOT have mental illness at all.
Homosexuality is NOT a mental illness and has been long removed from the DSM so you cannot compare homosexuality to BIID or SID.