The traditional family also creates a natural support system of and extented family grand-dads and grand-moms; Aunts and uncles. Many of which in a traditional family setting have a relationship with the children which is a benefit to the child.
A permanent closed and committed relationship. It is not hard to see from the standpoint of raising children why societies have adopted a committed relationship between mom's and dad's to that the next generation grows up to be able to benefit the society.
One would be overlooking the obvious to suggest marriage makes no difference, and as such the government has provided tax breaks in the form of recognition of dependance for people who have children. There is no requirement to be married to receive these tax breaks.
For the two adults (without children) a traditional marriage may give them security and they benefit from the partnership; Being able to seperate different types of labor (Getting the food, Cooking the food). This security may help them in their work to the benefit of society but in many cases may make little or no difference to the society at large. However, todays marriage looks different from traditional marriage in that either party may ask and receive a divorce. Any arguement for security benefit from traditional marriage can no longer be applied today.
Maybe the only benefit for marriage without children for society is in the form of normalizing it as a standard; to assist the church in promoting marriage and promoting not having sex outside of marriage.
Marriage has many assumed contractual agreements; there is an assumed will (which can be replaced by an actual one); there is an assumed community property (which can be specified by a contract or living will); all of these assumed contracts can be specified by an actual contract or even be written with a different person or company.
The benefit of Same Sex Marriage for the adults is that they get to ask for whatever traditional married people have. And because of the "Marriage" petition the court to get it. If they believe that sex out side of marriage is a sin, they get to feel better about not having sex out side of marriage. Maybe they also need an affirmation that everybody knows they love eachother.
Appart from what the adults get from same sex marriage, society seems to get very little. Certainly this is not the arrangement that the church is looking for to promote a child friendly family.
