Don't we also have to question why the concept was defined in such a way, and by whom? Gays have probably been around as long as straight people, so why were they excluded when marriage was defined? Did it happen that way because of religions hold on the world and society, or are there other reasons to consider?
That's a very good question, a difficult and complex one to answer. However, not getting religion into it, and besides the obvious biological reasons for propagation of the species, marriage exists essentially because the institution has a very definite purpose which has served its function well throughout the ages.
Marriage enabled and supported the concept of a family: without it, what would stop men from creating several families and then caring for none, leaving women and children unprotected? Also, marriage and the exclusive sexual access it implies is a way to ensure paternity of the children that union generates.
Marriage probably originated in a time were women heavily depended on men to survive: it's a binding contract enforced by society where, in its basic form, the woman promises to give the man sex, offspring and sexual exclusivity, and the man, in return, promises to take care of, and protect, the woman and their offspring.
Anyway, seen from the reproductive point of view, marriage between people of the same sex serves no purpose because they cannot generate offspring.
The ancient Greeks, for instance, commonly had same sex relationships, usually between adult men and adolescent boys (over 12), the boy always taking the passive role. This, however, never resulted in marriage, nor, I believe, would such a thing ever cross their minds. In fact, there was a social stigma for adult to adult same sex relationships, the stigma, however, being reserved for whomever took the passive/feminine role.
But marriage goes far beyond the purpose of offspring, as it does not end when the two partners can no longer procreate: it is also an institution in which the two partners promise to take care of each other until the end of their lives.
From this last point of view, marriage between people of the same sex does make some sense, but only if you chose to ignore for a while that homosexuality is a deviation from the true objective of matting, which is propagation of the species.
However, you cannot dissociate the other purposes from marriage and still call it a marriage.
Gay people have barely acquired the right to marry each other in some countries and they are already demanding the right to adopt children due to their inability to procreate. Isn't this odd in and by itself, even before considering what such behavior might do to the very fabric of our society? Are those in same sex relationships considering those potential effects and consequences even for a second? No, they only care about satisfying their own needs and wants. So where will it stop?
Men and women are different, each with different strengths and weaknesses, and therefore complement each other. This is not sexism, it's a fact. It starts with the fact that women can get pregnant and men can't. Even the brains are wired differently (the corpus callossum is thicker in women, which allows their right and left hemispheres to communicate better, for instance). Men are not superior to women, but neither are women superior to men - they are just different and complementary.
To succeed, men and women have to work as a team, each with a very specific role. When you start blurring or deliberately ignoring these differences, you end up with two people trying to play the same role, and that never works. Confusion and belligerence ensues - instead of being allies, men and women become 'enemies'.
Children learn to categorize themselves by gender very early on in life. A part of this is learning how to display and perform gendered identities as masculine or feminine, and this implies that masculine and feminine roles should be well defined within the family. It is bad enough that this is no longer clear cut in traditional families - how can then those roles be well defined in a gay relationship if both partners are of the same sex?! They can't, and they aren't.
Are we really willing to sacrifice a whole generation to find out what happens when we no longer have separate and well defined masculine and feminine roles? And, assuming the results are not so good, will we be willing - or even able - to backtrack then?
Why are they not? I love my partner beyond words, and we both support each other in many ways. She's the best friend I've ever had, outside of my brother. But obviously I've no desire to marry my brother (incest, a game all the family can play ). So that means only procreation isn't part of the equation. Is that such a bad thing? There's a lot of procreation going on outside of marriage. If we're logical about it, the purpose of sex is purely for procreation, something a gay couple can't do, but people have made it so that sex is now more about pleasuring the senses, not procreation. Which removes sex from its intended purpose and makes it a hedonistic pursuit for the majority. Which means the majority has created a double standard.
You said it yourself, you love your brother but you have no desire to marry him. So, marriage is not a requirement to demonstrate love. Why then demand something from society which, by definition, is reserved for people of opposite sexes? Why not be satisfied with the fact that society already tolerates same sex unions?
As for sex being used for purposes other than procreation, this has, in fact, always been the case. However, there were also social controls and restrictions in place to counteract this and balance things out - controls which mostly don't exist anymore.
Is this good? From a selfish point of view, it's great! Never has it been this easy to get free sex! But what price are we paying for this? Lets see:
Sex obeys the rules of supply and demand. When sex is scarce, men are more willing to go the extra mile in order to get it. Here is the basic argument by social psychologist Roy Baumeister: men like sex more than women and so, in the market for sex, they represent the 'demand'. Women like sex less than men, so in this market they are the 'supply'. In short, men have to compensate women in order to entice them into having sex.
In this market the women collude with each other by agreeing to reduce the supply of sex which has the effect of driving up the price. On a market for sex where women are colluding to keep prices high there is always an incentive for one woman to deviate: she can always offer sex at a lower price and capture a large share of the market. However, this would also result in the other women calling her a slut and in her being ostracized (the social control).
Men had their own set social controls, although very different from those applied to women: it was very common for men to have sex or even a mistress outside the marriage. Even if the wife found out about it, she would generally tolerate this and pretend not to know. Why? Because the alternative - divorce - was unthinkable at the time. BUT wow to the man who abandoned his family in order to live with his mistress - such a man would be despised by all! Wow to the man who did not provide for his family!
This is how that cliche of the love triangle where the mistress is eternally waiting for the man to leave his wife and marry her instead came about. Men promised they would but never actually did because they were bound to their families. As Elizabeth Abbott wrote, 'Mistressdom, in fact, has everything to do with marriage. It's an institution parallel and complementary to marriage, and it evolved to accommodate the sexual double standard that tolerates adultery in husbands but condemns it in wives'.
And so there was a balance, and things were kept in check. Not that I condone what is at the base of this balance (the double standard), but, in the end, men got what they wanted and so did women.
Then women became financially independent from men and this changed everything. Because women no longer needed men’s resources, they began to increase their supply of sex on the market. Little by little, sex became cheap. So cheap, in fact, that men no longer have the need to commit or stick to a relationship in order to get sex.
The irony of this is that by giving sex away, women also lost the leverage they had on men, i.e.; the 'power' they once had. And now they complain that men put off commitment and keep things casual for as long as possible.
Anyway, in part because of this new found financial independence, divorce became common and socially accepted, almost the norm (in America 50% percent of first marriages, 67% of second and 74% of third marriages end in divorce, according to Jennifer Baker of the Forest Institute of Professional Psychology in Springfield, Missouri).
Most people will defend divorce on the basis that nobody should be stuck in an unhappy marriage. True, but this is in part based on the big *lie* that most marriages of old were unhappy (not true!), and, furthermore, the long term side effect (remember in my previous post where I mentioned you have immediate consequences - which might be good - and then long term consequences - which might be bad?) is that now almost nobody is willing to go the extra mile to maintain a marriage, and just quit at the first sign of real trouble. Remember the 'for better and for worse' vow? With divorce being so easy and so common... when the going gets tough, the tough get going. This makes a mockery of marriage, which is a *contract* between two people for life. If there is no price to pay for breaking a contract, then it's obvious that the contract is pretty much useless. It's no longer a contract but a vague promise.
So what do we have now? Single parents trying to juggle their careers and their children, leaving little time for the latter. Worse, people used to live in small communities where the whole community (or at least the immediate family which normally lived in the same household) shared the burden of educating and taking care of the children, and this is no longer true. The education of small children is a full time job and we are now neglecting them because, with both parents working, we simply don't have enough available time.
As a result, our children feel lost and abandoned, and then we have unthinkable things such as the Columbine High School massacre, children as young as 12 murdering and robbing people, or joining gangs so they have a sense of 'belonging' and 'protection', etc...
Furthermore, women these days are as promiscuous, if not more promiscuous, than men ever were: infidelity is *everywhere* and is essentially considered 'to be expected' - if not even considered to be 'normal' - even though it's effects remain as devastating as they always were. I can't help but remember what one woman I knew once said to me when she was justifying herself for having been unfaithful to her boyfriend: 'hey, if men do it, why shouldn't we?!'.
Since when is it ok to correct one wrong with another wrong? Unfortunately this 'an eye for an eye' mentality seems to be prevalent in feminism these days.
The implicit trust that was once in the institution of marriage is gone, and nothing is 'forever' anymore. Most people go into new relationships with both eyes wide open, already expecting it to fail, simply because nearly everybody has already been bitten before. The Apple tree is rotten to the core. Very few people are able to walk into a new relationship without carrying with them severe emotional baggage and distrust caused by previous failed relationships - and that is half way to make the new relationship fail as well.
People are more alone now than ever before.
Anyway, apparently good things (women's independence, the freedom from sexual repression, the economic boom that occurred because suddenly both parents were producing, etc...) ended up giving fruit to some really bad things, either because we took those good things too far or because we were unable - or didn't care - to come up with alternate mechanisms to restore the balance.
But how can a minority become the majority when the minority is outnumbered.
For instance, by reaching key places of power and then making sure only those who agree with them are able to do the same. All in a very hidden but legal way, of course.
I don't want to become the majority. I would, however, like for my voice to be heard, and if what I'm saying makes sense to the majority, for it to be acted upon.
Goes without saying. But what is happening now is that things that do not make sense to the majority are also being acted upon, with those who resist them being called bigots, close minded, etc...
I consider myself to be pretty altruistic by nature. But it's not a part of me that I cherish quite the same these days. I've found time after time that while it's a highly commendable trait to have, there are far too many who are willing to abuse it by taking it for granted. I am still altruistic to this day, but it's not something I show to others until I feel I truly trust them. Which is a shame really, and a sad comment on society. The only other option is for me to act in such a way that I lose the right to call myself human. I tried it for a while; it sucked!
Being altruistic is a good thing, so be true to yourself and don't let others destroy it. But learn to defend yourself too (i.e.; do not throw your pearls at swine, they will not know how to appreciate them). If someone takes advantage of your altruism, it's not your fault - the person who took advantage is in the wrong, not you.
Anything done to excess is bad for you, that includes exercise. But yes, we should strive for the middle ground. Are you sure you're not a Buddhist, Jorge, 'cause they also believe that we should travel the middle path, instead of opting for too much of one or the other. Oh, and a totally pointless fact for you. Apparently, eating nothing but rabbit (no vegetables or anything else) will kill you. It has something to do with rabbit absorbing all the bodies vitamins/minerals, or requiring all the bodies vitamins/minerals to break it down. Anyway, now you're head has got that totally useless information just like mine, mwuahahahahaha.
Ahah. 
Didn't know that one about the rabbit. Btw, you do know that my name is 'Jorge Coelho', and that 'Coelho' means rabbit in Portuguese, no? lol
Anyway, I noticed other replies since I started writing this, but I'll tackle them in another post.
