If we legalize gay marriage, why can't 2 women and a man get marry or why can't a brother and sister get marry? And why does marriage have to be in 2? There are plenty of cultures where men have many wives and perhaps less common women with many husbands. There are marriages between minors and adults and between 2 minors! Is there is an age limit needs to be concern? Even if UNION have all the rights and benefits of a marriage, it wouldn't be the same concept as a marriage, correct? Where is the limit if WE NEED TO BROADEN THE CONCEPT OF MARRIAGE?