All societies have laws that are based on what things those socieites believe are moral and what things they believe are immoral. For example, we have laws in the United States against women going topless in public and against men or women exposing their genitals in public. There are no reasons for these laws other than the fact that our society thinks that those actions are immoral.
If same sex marriages should be illegal in the US, it is for this same reason. They should be illegal (you can argue) if the majority of people think that they are immoral. Some people argue that laws should not impose some people's morals on others, but the truth is that we do that with so many of our laws.
While I, personally, believe gay marriage should be legal, I also understand that that is a matter of my own morality and nothing more. I cannot draw a moral and principled line, for example, to explain why gay marriage should be legal but polygamy should not be. It is just a matter of what we think is moral or not.
So, if gay marriage should be illegal, it is because enough people find such marriages to be morally offensive. Society has the right to (within limits) make laws to enforce its morality.
I hope this question makes it to the Discussion Board, as it is a matter still hotly debated.
I for one do not think they should be illegal. Those who oppose same sex marriages do so on the basis of marriage as a foundation of a stable society, marriage being an institution comprised of a man and woman. They argue that if/when marriage is morphed into any other form, then the very foundations on which society is built would collapse.
Not only do I disagree with this position; I think the Equal Protection Clause of the 14th Amendment guarantees people the right to marry regardless of sexual orientation. I note that just recently, the Obama Administration has said it will no longer defend the Defense of Marriage Act in Court. The time has come for people to accept those of same sex orientation as normal people who have the same rights as those who are not so inclined. I am curious to hear the opinions of those who disagree with me.
Same-sex marriage, also referred to as gay marriage, is marriage between two persons of the same sex. The federal government of the United States does not recognize the marriages of same-sex couples and is prohibited from doing so by the Defense of Marriage Act. Same-sex marriage is legal in three states as a result of court rulings and in two others—as well as the District of Columbia—through votes in their respective legislatures.