Explain reasons behind trans-sexual people

Although we would like to think maleness and femaleness are either/or states this is not the case either in terms of gender role or anatomy.

First, let's take the case of gender role identity. This is largely dictated by the society in which we grow up, as evidenced by the variations we see in foreign cultures. For example, in Hawaiian culture, there is a specific kind of effeminate male known as a Mahu. Mahus tend to have effeminate mannerisms and sing falsetto, often times having voices that women would envy. However, they may be either homosexual or heterosexual. Many Mahus are happily married with children and no homosexual yearnings...but if a Mahu showed up anywhere else in the United States, he would likely be classified as "Gay."

When we look a little more deeply into gender roles, we find that we tend to assign high-risk behaviors to men and low-risk behaviors to women. No doubt this evolved in response to the demands of the harsh environments of the past. Nowadays the standard gender role assignments are less imperative.

So what we have is a situation where we have socially defined maleness and femaleness as necessary polar opposites, when they may be fairly arbitrary cultural responses to survival needs. When a person is born into the social structure they are then forced to choose, even when they are not predisposed one way or the other. Psychologists tell us that each person has both a masculine and a feminine side within. 

We find a similarly forced polarity when we look from an anatomical perspective. It can be shown that as a fetus develops, it has the capacity to turn into either sex and differentiates as it develops. Although we might like to think that children are born one way or the other, this is not the case. Aside from the occasional "true hermaphrodite" there are a variety of different genital configurations.

Some females are born with clitorises large enough to resemble penises and some males have complications when their testicles don't descend. Doctors may regard certain genital configurations as birth defects and surgically alter the newborns in what they think is their best interest.

So what we are left with is a situation whereby one is assigned a polar gender role based on how closely their genitals resemble one sex or the other. For the majority of people, this seems to work. For some, this doesn't work at all. A person may posess genitalia from one sex and feel more appropriate in the gender role of the opposite sex.

This is situation is further complicated by adding sexual preference to the mix and this may be the deciding factor for the decision to have an operation. Althougth it may appear inconceiveable to a heterosexual that one would want to switch their parts, it starts to make a little more sense if you imagine waking up as the opposite sex.

In the interests of tolerance, imagine that you have the genitals of the opposite sex. You feel exactly as you currently do, are attracted to exactly whom you are currently attracted to, and love exactly whom you already love. However, you happen to own the wrong set of parts. If you wanted to make love to your husband, wife or lover ever again, you might think about getting an operation.