I read your piece, “Say no to same-sex marriage“. I understand that you are a young teenager and I applaud you sharing your ideas so articulately in an open forum. However, in relation to this matter, you need to get your facts straight. First of all, marriage is an institution older than monotheism itself. It is not an exclusively religious institution; it has a secular history (e.g. / ancient Greece) that also predates Christianity, Judaism, and all other major world religions. There are as many definitions, attitudes, and reasons for marriage as there are cultures on this planet.
In fact, the closest thing to a universal denominator for marriage worldwide (and this has only seen change in the past hundred years or so) is that it is an economically and socially practical move for families with daughters. It is a tradition based on pragmatism and maintaining social order. This explains why historically, polygamy and polyandry were both accepted in different societies in response to unbalanced male-female populations and economic hardship (check out Anthropology 101 when you get to college).
Furthermore, there are several cultures in which “gay” marriage has always been accepted. Several female chieftains in sub-Saharan Africa take wives, and bi-gendered priests in India and Brasil may marry women or men, depending on their own sexual inclination. Even within the Christian faith, there are an increasing number of denominations (part of that 55%) that bless same-sex marriages; a lot of people who know the Bible a whole lot better than you two have different ideas about who can and cannot get married. Your debate about the intrinsic nature of marriage is misinformed, more the product of your dogmatic religious beliefs than your actual amount of knowledge concerning the matter.
Nowadays, in most societies where women are on more equal footing with men in terms of civil rights, mutual love plays a much larger role in who gets married to whom. This, again, is a relatively recent development in the ever-changing institution of marriage. Since love has become the keyword for why two people would get married in this day and age, the institution of marriage has become relevant to some gay people. So how relevant are gay people themselves?
There has been statistical research compiled, such as in the well-known 1993 Janus Report, which reinforces the estimate made in 1948 by Alfred Kinsey: close to 10% of the human population is gay. This is no mere minority, and certainly cannot be compared statistically with brother-brother and son-mother couples. This is an issue that must be looked at as a matter of civil rights, not special rights; gay citizens comprise a huge segment of the population.
I personally believe that gay people have as much a right to marry as straight people like me and you. This is because I endorse the new definition of marriage, which is a commitment by two people in love to officially build a life together. Canada is not Eden; times have changed.
As far as your appraisal of homosexuality and bisexuality goes, I would be very careful before telling the rest of the world what makes a person gay, straight, or bisexual. Maybe the conclusion you came to is the result of your own sexual inexperience, but people don't simply choose whether or not whether they want to be gay or straight; an inherent sexual attraction has to exist.
I'll quote a source from WebMD, a resource I think you should definitely check out: “studies in male twins have suggested that between 40%-60% of the variability in sexual orientation is due to genes.” The reasons behind why someone becomes gay or bisexual are not fully understood, but that doesn't mean that you should jump to your own conclusions without educating yourself about the matter first.