The very nature of "civil unions" for gays IS a redefinition of marriage for gays and lesbians.
It stinks with that old "separate but equal" BS that existed for years and we all know that was anything but equal. For all the hoopin' & hollerin' in the last week about how far the USA has come in her ability to get past the old ghosts of prejudice & bigotry that has haunted her for so long, ...the fact that people are unable to see this very blatant bigotted attack upon the civil rights of gay & lesbians indicates the USA has not come as far as she thinks she has, ...or at least as far as she needs to be. I find it very sad. 
There is a big major difference between the two types of things you are talking about.
First, prejudice against anyone is wrong, no sain person can argue that with any basis. Now, denying certain civil rights to anyone based on skin color or race is also wrong...obviously, it's not like anyone can control their race or skin color. Now, you probably think you know where I am going with this, and you're partialy right, but that's not the full story.
Yes, I believe homosexuality is a choice, not something that you're born into. I know some can point out studies that say otherwise, but there are more studies that prove this fact that it is choice, not genetic. Our behavior in all aspects of life is largely determined by our environment, who we associate with, how our world view develops, etc. Something I read that I found very interesting a few month ago (sorry can't remember off hand where, I'll try to find it) was that in a survey of homosexual men, most, not all but a strong majority grew up in single family homes where the father was absent. Inevitably these men became products of their enviroment, but it's still amounts to choice.
The main topic at hand: marriage is by no means something that can be argued that is due to all with whom they wish under the constitution. Under our constitution which by way the civil liberties act was born, requires that all people are entitled to their pursuit of life, liberty and happiness. Happiness though under the constitution does not mean actual happiness, it refers to property. That's how the actual constitution reads, people have simply substituted property with happieness. What this means is everyone is entitled to their fair share of ability to reach their dreams, and to protect against intrusion on anything that would hinder this ability. People are granted this freedom, but what they do with it is choice in regards to success or failure.
With what I said, some might say that preventing homosexuals from marrying hinders their abilities to these inalienable rights. It is taking away their "liberty" to choose how they live their lives. I simply do not see it this way at all. It obviously goes against the establishment of what marriage is, it is a slap in the face to those who are heterosexual and find themselves married and by what that stands for.
