I want zero children.

But, I will say this: if you are with a person who won't consider adoption, but you want that to be an option for you, then you should communicate that in a healthy way.

Its not something that I would bring up on a first date, mind you. Sometimes the "kids" conversation comes up. You could always say that you have always dreamed about having a family with a spouse (if that is your thing), x number of kids, white picket fence, 2.1 cars, and a goldfish. It helps to get that kind of stuff out of the way.

But I would wait until a couple of dates before bringing up the nuance of how you would make that dream come true.