I want kids, the g/f doesn't, what do I do?

Long story short, I want kids at some point in the future, and my g/f does not. We’ve been dating for almost two years and moved in back in May. I have always wanted to have 2–3 children. I am open to adopting a child, but would like at least one natural child. My parents divorced and remarried new spouses, and I ended up with 9 total siblings. My g/f was adopted herself, and was an only child to her adopted parents. She has apparently for some time known she didn’t want children, I believe even of the adopted variety.

By in large my philosophy has been to avoid this issue as even though I want kids I’m not really close to the point in life where I want them… so why rock the boat ya know? But my g/f has brought it up increasingly since we moved in, and it’s beginning to weigh on me.

Do we continue on in this relationship, knowing at some point we’ll meet this impasse? Do we just call it off now before it becomes even more involved? How do we go about compromising on this issue if that’s the plan, since it seems pretty much an all or nothing scenario?

What do you suggest?