[@Vetis]no. That is not the case.

A legacy is merely...well that God has taken an interest in you. It's sort of...influences you.

In no one is it related to being the child of a demigod. 

In this, we are children of the gods and a human. 

Vicier can explain it better. 

But for example, Connor is the son of Morpheus. His legacy is Athena, as he is...well a nerd XD she in no way gave birth to him. But in some way, he is like Athena. 

I hope that helps.