 A big one is how many kids do you want to have? If one wants to have 17 kids and the other one doesn't want to have any, well, that's going to be a source of constant tension and trouble in your marriage. You need to figure those things out maybe before you get hitched. I would say if you're young and have childbearing years and you don't have some significant health issue, not wanting to have kids is probably not a biblical desire. It's probably not a God-honoring desire.