The argument for legitimizing same-sex relations, either morally or legally, is based on a number of assumptions. In order to help people better understand the argument and make more informed decisions, I will shed light on a few:
Assumption #1: Homosexual identity should be regarded just as highly as religious identity.
The identity we choose to represent us can be our gender, occupation, family, cultural background, sexual preference, religion, diet, team loyalty, or political affiliation, just to name a few. Are these categories equal, though, in import? Let's discuss just two.
How is sexual preference different from religious belief? The answer should be clear from the question itself. Your religion, or philosophy, is the template for your beliefs about the nature of reality -- people, God, the universe, etc. -- which dictates what behaviors are morally appropriate. A homosexual identity grows from thoughts and feelings concerning same-sex preference, or desire. Without trivializing the nature or intensity of these feelings, I would like to point out the difference between desire and belief.
I would love the euphoria that comes from doing ecstasy. If I have done drugs in the past, my craving is constant, innate, and overwhelming. I think about them often and rationalize using them again: Ecstasy is a party drug, right? It doesn't hurt anyone! However, because I know drugs will have a negative effect on my life and on society in the long run (and I know my mom would be disappointed in me), I choose to suppress these desires. In this case, my rationality (thoughts based on true belief), overcomes my rationalizations (thoughts driven by desire).
Belief, not appetite, should determine our personal code of morality. C.S. Lewis said, "If 'being good' meant simply joining the side you happened to fancy... then good would not deserve to be called good" (Mere Christianity, p. 34). Regardless of whether I call it religion or philosophy, my rational, moral beliefs (or we could even stretch that to FAITH) allow me to control my desires, master my appetites, and channel my energies to accomplish and become what is difficult and healthy and good. “Reason saves and strengthens my whole system, psychological and physical, whereas that whole system, by rebelling against Reason, destroys both Reason and itself ... Nature may be rebellious. But from observing what happens when Nature obeys it is almost impossible not to conclude that it is her very ‘nature’ to be a subject” (Miracles, 4.13).
At this point some may say, I am not driven by appetites any more than any other person is driven by theirs. Or, they may say, appetites are logical because they indicate what our bodies and minds need. This may be true. But if we allow that argument, we open a can of worms including pedophilia, bestiality, bigamy, adultery, incest, and many other things that as a society we still generally consider reprehensible. In order to avoid this dangerous spiral, we must clearly distinguish what is true from what we would like to be true merely because it accommodates what we want.
C.S. Lewis attests to the importance of distinguishing between desire and belief in choosing a denomination:
"The question should never be: 'Do I like that kind of service?' but 'Are these doctrines true: Is holiness here? Does my conscience move me towards this? Is my reluctance to knock at this door due to my pride, or my mere taste, or my personal dislike of this particular door-keeper?'"
I am not arguing that the choice to pursue same-sex attraction is irrational. Those who make the choice to "come out" with their feelings and live the lifestyle openly surely spend an enormous amount of time making the decision. However, no one would say that they chose to be homosexual for purely rational or moral reasons. The fact that the gay community claims it is not a choice (and we have no reason to doubt them) attests to the non-rational impetus of their decision to "live out"; it indicates that no one pursues a homosexual lifestyle solely because they feel it is the right thing to do. Their decision always begins with desire--usually unwanted. Whether people choose to remain in the proverbial closet or come out (and may have logical reasons for doing so) is not about who has the strongest feelings. It's about which individuals choose to allow their desires to influence their beliefs and which individuals allow their beliefs to control their desires.
So, in response to this assumption, beware of the false comparison between groups who have a faith-based identity and those that are desire-based. They may both be persecuted, but they are not the same. While beliefs most certainly can change, we must be brutal in our examination of these changes to be sure they are motivated by truth and faith, not by appetites and desire. If not, we risk rationalizing away both our sense of morality and our sense of reality, and losing our humanity in the process.