[The Green Goblin]

You're also arguing that people who are too elderly to have kids or adopt them should not allowed to be married by the state.

[BMiles2112]

Good point. Correction to my #76. The state should not endorse the relationship if there are NO children involved, and never will be. An elderly couple who has children, grandchildren, etc. from past relationships could make a case for the state to endorse it, if they were involved in, or intended to be involved in, the raising of grandchildren, etc.
(I know, your post wasn't to me, but you raised a good question.)

[Steel Wolf]

Okay, one more time -

The institution of marriage broadly exists for all men and women, because men and women can potentially have children. This is a social construct that exists because civilization cannot exist without a constant supply of people. We protect marriage and make it special because it is an investment in the future of humanity.

NOT EVERY MARRIAGE needs to produce children for the institution to be valuable. NOT EVERY MARRIAGE will produce happy, well adjusted, productive citizens. Still, the institution works fine, because it produces enough.

Gay marriage has zero potential to produce children. None. They confer no potential benefit to society.

So, a million hetero couples could produce five million new people.

A million gay couples would produce none.

If some hetero couples produce more or less than others, no big deal, so long as a sufficient supply is kept up. Letting all men and women willing to accept the responsibility of marriage do so strengthens the institution. In some cases it won't pan out in the short term, but long term, keeping marriage special, honored and protected is worth it.