Study of Structural Functionalism Discussion

I’m working on a sociology question and need guidance to help me learn.

Prompt: You may or may not agree that marriage is necessary before having kids, but why do you think that marriage is so often seen as the “right thing” to do before having children in the US? Consider the cultural norm of marriage preceding children from each of the Big Three sociological lenses to explain how a theorist from each side would explain that norm.