Welcome!
There is a fair body of evidence to indicate that there is a genetic component to intelligence (including giftedness), but it's not, of course, the only factor.
FWIW, children are (as I'm sure you realize) hard work no matter what their IQs are! Give yourself permission not to be perfect as a parent. It's enough that they know they are loved, cared for, and valued as they are. As you spend time observing them and their interests, they will begin to show you how to feed their unique gifts and joys, and to support them across their obstacles. If you feel comfortable telling us a bit more about the particular form of hard work they present, I'm sure this community will be able to come up with some thoughtful tips.
