I always used to laugh at these people, before I knew the truth. I always used the think that transsexual meant that you're a transvestite. That is far from the truth.
Transsexual individuals are people who are born with a different genetic make-up.
They might have a slighter smaller genitalia, or they might have slightly larger genitalia. It doesn't mean that they are freaks. After all, if they didn't say anything, you wouldn't even know the difference with most of them.