Some people don't feel like the person they see in the mirror.

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The idea of getting stuck in the wrong body sounds like the premise for a movie -- in "Freaky Friday," a mother and a daughter swap bodies, and in "Big" and "13 Going on 30," teenagers experience life in an adult's body. These movies derive their humor from the ways in which the person's attitude and thoughts don't match their appearance. A teenager trapped in her mother's body, for example, revels in breaking curfew and playing air guitar, while a teenager trapped in an adult's body is astounded by the trappings of wealth that come with a full-time job. We laugh because the dialogue and actions are so contrary to what we'd expect from someone who is a mother, or from someone who is an employed adult.

But for some people, being stuck in the wrong body is anything but a joke. A transgender person is someone who has a different gender identity than their biological sex would indicate. Sex refers to the parts we were born with; boys, we assume, have a penis, while girls come equipped with a vagina. Gender is different from sex and includes the behavior that we associate with men and women. Little girls, for example, would be expected to play with dolls and wear dresses, and little boys are known for their penchants for roughhousing, camouflage pants and monster trucks.

Sometimes, a young boy may want to wear dresses and have tea parties for a while, and it's nothing more than a phase that eventually ends. Other times, however, that longing for the trappings of the other gender becomes so intense that the person experiencing it can't function anymore. The person's own body seems like a cruel joke and becomes hateful and appalling. People who feel this way are termed transsexuals, and they may choose to undergo a transition from one gender to the other. This article will detail the stages of the process of gender reassignment.