And I believe this is a large, but unspoken motivation among the gay activists. It's just covert destruction.
So what? That can happen now. It isn't "destruction," it's life.
Your children could adopt, leaving their estate (and what remains of yours) to people who aren't "blood relations". They might choose to exclude their kids from any inheritance (perhaps, for example, giving it all to charity). They could squander your estate before they can leave anything to their kids. Or your children might even choose not to have families at all.
You only get to control your estate for the one generation. It's all out of your hands after that.
With all due respect, this by itself is a very flimsy excuse to ban gay marriage.
We're not talking about banning gay marriage...we're talking about whether it should be legalized. It's not currently legal.
That's Life?!?!
I'm going to guess that you don't have any children. One thing that being a parent changes in people, is that they have more concern for the future. It matters what happens in the world. The most intimate connection a human has to the future of the race is one's own child. Saying that the impulse to influence and protect the future through one's progeny is a "so what"...just tells me you already gave up