i was just thinking about this, and wondering if there's other animals beside human who are transsexual. obviously, humans can do something about it, but since human is the smartest most capable species in the animal kingdom, there's much more prominent distinction in the gender roles. i'm thinking if say a cheetah was born male, but had a female brain. would they adopt the female gender role without resistance from other cheetahs? would they feel out of place amongst the females with their different body appearance?

While I don't really have any scientific data to back this up, I'd have to say that it's most certainly possible. It would be rather close-minded to think that humans are the only species to experience such a thing, after all. I know that some animals can be homosexual or bisexual, and sometimes even resort to stealing babies from other couples (relatively rare as I recall). Then again, I'm not so sure that an animal such as a cheetah would have the option to explore such a thing, regardless of what their brain actually is. I believe that if they were in the wild, they would be focusing more on survival than anything. If they were in captivity though? I'm not so sure.

I'm a bit indecisive on the matter, I have to admit.

On a side note, and this may or may not be related, Hyenas are known to have opposite gender roles than what we would consider "normal". Females are the dominant sex, and their vaginas look almost exactly like a penis (they are also apparently very painful to give birth from). In addition they grow much larger and stronger than the males. I'm curious to know what would happen if a male hyena was born with a female brain, or vice-versa.

There are some species of fish that do biologically change genders to meet the constraints of their particular gender-based social structures (http://en.wikipedia.org/wiki/Sex_change#Sex_change_in_animals) and some frogs change gender to facilitate reproduction when there is a shortage of a given gender (http://www.newton.dep.anl.gov/askasci/bio99/bio99128.htm).  While this specific phenomenon is not found in mammals, there is no reason to assume that the psychological phenomenon that occurs in humans is not occurring in other mammals.  However, considering how few animals are even capable of self-awareness, it seems unlikely they would be able to understand that their brain is telling them they're the wrong gender or really understand what that means.

Now, since we seem to have determined the area of the human brain that determines gender, it is not unreasonable to assume that, if the notion of gender expressed based on brain chemistry is considered fact and a budget would be given to a group to perform such a study, we could study the workings of animal brains to determine whether they are transgender.

But then what?  Do you administer hormones or perform genital surgery on the animal?  Do you attempt to provide an environment that would nurture their desire to be the opposite gender?  Think of what different lobbyists would have to say about it!