EllEzDee said:
Your gender is how you were born. "I feel like (the opposite sex)" doesn't cut it for me. I feel like being rich for a day, but if i used that to get into someone's pants, it'd be a hell of a thing to explain the night after.
I'm going to attempt to change your mind rationally.
I will assume you are a normal male; should this not be the case, amend my argument appropriately.
During your embryonic and fetal development, your Y chromosome encoded for chemical messengers which caused at least three very big things to happen. First, a group of compounds called androgens, of which testosterone is just the best known, caused a group of cells called the Wulfian ducts to become the male reproductive system. Second, another messenger, Mullerian Inhibiting Factor (MIF) shut down the Mullerian ducts from making female bits. This meant that between your androgens and MIF, you developed a normal male reproductive system. This pattern seems to hold across mammals ranging from rats to humans.
In addition, there were chemical receptors in your brain which detected androgens and changed the sex of your brain.
Notice how this system can break down? If the brain and developing reproductive system do not get the same signal (become male), a "female" brain can develop inside a "male body", or vice versa. If all androgen receptors have failed, an individual with an XY genome can develop testicles, female genitalia, a female brain, but fail to develop internal female reproductive structures thanks to MIF still being produced. These these cases are quite real.
Naturally, I do not expect you to simply take my word for it. I just googled "Androgen Receptors in the Brain," skipped any articles on Wikipedia, and here are just the first five results. You can find thousands of more articles in scientific literature if you wish.
http://www.nature.com/nature/journal/v282/n5736/abs/282308a0.html
http://www.pnas.org/content/101/6/1673.short
http://edrv.endojournals.org/content/4/2/171.abstract
http://www.ncbi.nlm.nih.gov/pubmed/1734159
http://www.jbc.org/content/251/13/4047.abstract
So, what do you make of a person whose genitals received the message and gave rise to male structures, yet whose brain during development did not? This person's brain does not develop like a male's; it develops like a female's. There was no choice in this; it's genetic weirdness which happens to human beings. They've made no decisions which changed anything. It is without exaggeration something that happened entirely before they were born.