Same Sex Marriage: Equality?

Marriage has been traditionally defined as a union between two people, of different sexes, that are over the age of consent, and that are not related.  If we alter or ignore these restrictions and permit same-sex marriage, do we not risk opening the floodgates to the sanctioning of all types of familial arguments?

I believe that love is love regardless of the sex, however I feel as if everyone should have the same rights no matter if it's a same-sex or opposite-sex marriage.  One of my reasons for saying this is because of insurance. Most businesses and corporations now allow same sex couples, that are living together, but are not married to be covered on insurance, however, if it is a man and woman that are living together and are not married they can't be covered on each other's insurance. This is very unfair, what's done for one, should be done for all and everyone, no matter who they are married to should be treated equally.

Marriage is a public institution because it serves two public purposes: bringing together a man and woman for the reproduction of the human race.  The quality of their nature is directly related to the quality of life in that society. The existence of future generations of children is fundamental to the survival of any society.  Bonding the man and woman whose sexual union produces a child to one another and to that child is by far the most efficient way of ensuring that nature.

Advocates of same sex marriage claim that this concept cannot be the purpose of marriage because some opposite-sex couples marry without procreating. Opposite-sex relationships are the only type capable of producing children through natural intercourse and the only ones assured of providing children with both a mother and father.