This represents my current thinking on the incredibly controversial topic of gay marriage.
Those who are in favor of gay marriage are intensely concerned about people operating out of knee-jerk hatred and bigotry toward homosexuals. There is the knee-jerk fear/hatred of gay people to be concerned about. There is also a subtler bigotry in believing that all people who have an opinion in favor of limiting marriage to man-woman are bigots. There is a concern that an argument in favor of limiting marriage will encourage bigotry for the sheer fact that it is an argument of the same conclusion as those with bigoted tendencies. I am convinced that the bigotry or lack thereof of an argument on this loaded topic of gay marriage needs to be evaluated more as a consequence of the substance than the conclusion. It is for this reason that both sides of the fence on this topic need to present arguments that are as thorough and honest as they can be.
There are many deaf people want to believe that they are "differently-abled" and not handicapped. This is a very human tendency, to want to make the best of things, to see things in the most positive light. This tendency, as understandable as it is, cannot be allowed to do injustice to the truth; there is something lacking in being deaf. Even as there is a richness to life one can experience despite ones deafness and maybe even somewhat because of one’s deafness, being deaf is at the end of the day a handicap.
There is an aspect of human experience that is only available across the experience of male and female. There is something experience of the otherness of the other sex that cannot be duplicated. Male to male and female to female will not do even if it is "butch to femme". At the end of the day it is a sexual handicap. As Dennis Prager has said, there is an element of lack, of loss of tragedy to a homosexual relationship, and parents who learn that their child is gay have a right to process a certain sadness.
Those who feel like a woman in a man's body's and vice versa have a disorder, that by definition is not the best expression of nature. Being gay is sometimes a result of having a full blown version of this disorder or it is a result of having a lesser version of a gender disorder. Gay men have a more a female orientation to their brains than straight men and lesbian women have a more masculine orientation of their brains than straight women.
Those who are gay/gender disordered have a balance of tendencies that is out of sinc with their bodies and the experiences that the body is best designed for. Penises are designed to fit into vaginas and it is a tragedy when they don't. A baby is best brought into the world from the womb of a woman who is married to a committed man. From the perspective of the best and most naturally ideal expression of sexuality, a gay union is a tragedy of nature and a tragedy of choices, even as a gay committed monogamous union can be fulfilling and be better than gay promiscuity, and may be the best choice that a gay person can make with his/her life.
There is an aspect of being heterosexual that is a mere gift of nature that endows one with the ability to be horny around the opposite sex. Being heterosexual does not make one a responsible husband or wife. A person needs to consummate his/her sexuality with good choices. It is this dimension of choice that gives sexuality a fluid aspect to it that can be affected by society and/traumatic circumstances.
Sexuality in men and women can be understood as an apportionment of lesser and dominant tendencies. Men have masculinity as a dominant tendency and femininity as a lesser tendency. Men bond with women as a way to live out a part of their humanity (what is described as an anime) vicariously through the women that they are attracted to. The reverse is true for women.
The full and healthy expression of one’s tendencies, dominant and lesser, is found in a committed monogamous covenanted relationship with the opposite sex. There is natural raw material for this, but the natural raw material for this is not enough; it must be consummated by choices. The marriage ceremony is a ceremony of ones choices, as are other ceremonies that indicate rites of passage.
Under particular stresses, traumas and/or cultural pressures, men and women can turn away from a wholesome expression of their dominant tendencies and even turn from the dominant tendencies themselves. There are gay people who have felt gay and/or gender disoriented from as early as they can remember. There are people who act out in homosexual ways as a result of trauma. I have met both.
Those who do not recognize any dimension of choice to one's sexuality are of the philosophical bent that there is no real "free will" to begin with, that we are conduits of much larger natural forces. This thinking is the basis for promiscuous and adulterous behavior by people who say "it happened" and not "I chose to act". This thinking undermines the integrity of any marriage, whether gay or hetero.
There is a value to the ideal, to recognizing a hierarchy that places one human expression above another. To honor the ideal is not merely to honor the natural gift of having hetero tendencies; it is to also honor a particular set of choices within the dimension of choice that is a component of sexuality. Honoring the ideal by giving a special significance to a male-female union is not by any means a complete bulwark against any particular person’s choices to the contrary. Nevertheless, it is an important component of a society’s expression of a value system toward the goal that men and women bond in covenanted monogamous relationships.
And yes, there are hetero unions that do not bear children, that must adopt or use science to assist in becoming pregnant. One could argue that these unions are no more or less ideal than a gay couple adopting. This line of thinking is making a false equality that is based on a failure to recognize any ideal. Hetero unions with obstacles in having and/or bearing children are closer to an ideal that is expressed both in biology and choice. Of course it is true that a particular gay couple may have more to offer in certain areas than a particular a straight couple. The ideal is based though on this generality: a man and woman experience a unique richness in each other's otherness and so too does a child benefit from this richness, regardless of how "naturally" the child came to be in the relationship. Honoring the ideal is something that needs to be done by paying a cost.
There are understandable benefits that two committed people of the same sex can gain by acquiring the legal priveleges that now included in the legal package of a man-woman "marriage". However, our society needs a place to be able to acknowledge that there is a hierarchy of value the places a man-woman union at the top. It is true that a loving gay couple will be better parents than an abusive/neglectful hetero couple and may be better than a lot of non-ideal family-raising environments. Nevertheless, adoption agencies should have the right to give preference to man-woman unions. Our society needs to be legally protected from those who would advance the charge of "discrimination" for those who would use the legal equality of a gay marriage to demand that a gay marriage be treated as %100 equal in every dimension. Protecting those who would honor the hierarchy of value from the charge of discrimination requires that a man-woman marriage be given some sort of legal distinction from a gay marriage, even if it is a very slight legal distinction.
The problem with suggesting this is that the gay movement sees itself as a civil rights movement that sees itself in the tradition of black civil rights, where the legality of gay marriage is merely the legal wing of a moral, cultural and philosophical agenda. For much of the current movement to legalize gay marriage, the goal is not merely a legal triumph. It is an attempt to advance a moral system that understands it as being bigoted not to regard gay marriage as being every inch as ideal as a hetero marriage, only different. In other words, the force of opinion that is striving to make gay marriage legally equal to hetero marriage is the same force that is striving to make it 100% morally equal. -- and therefore morally repugnant to believe that there is a hierarchy of value placing a hetero marriage above a homo marriage.
Dennis Prager has also discussed a larger "meta-civil rights" agenda at work to deconstruct the very idea of gender, to thoroughly divorce gender from biological sexuality (“meta-civil-rights” is my term). Not all, but many of those who are interested in gay marriage are not interested so much in "marriage" as they are interested in advancing all forms of poly-gender expression, and gay marriage is merely the cause that has incremental practical value for the moment. Later on, the "times" will change and a new envelope of progress will be pushed.
It is this force of the gay marriage movement's deeper moral agenda that will operate as a cultural force to push that margin of flexibility that exists in human sexuality to in the direction of increased homosexual and bisexual expression. That is why I think it is misleading to say that studies have shown that kids do not have a greater tendency to be gay when they are raised by gay parents. In this day and age our society is not yet dominated with gayness. Straight kids raised by a gay couple in 2008 will still have a society to cross-reference their sexuality with that is still dominated by hetero-sexuality (even if it is promiscuous). With enough culture force, it is possible for societies to be dominated with normative gay behavior and pederasty "above the surface", such as the ancient Greeks and Celts. It is also possible for societies to have a lot of normative gayness and pederasty "on the down low".