פירוש על קידושין 66:7

Above we said that the son who is a scholar need not stand in front of his father. But should the father stand in front of him.
R. Joshua ben Levi says that the only reason he stands before his son is that his son is part of the Nasi’s (the political leader’s) household. But, the Talmud reasons out, that the reason the father says he should not stand in front of his son is that the father is the teacher. But if the son were the teacher, the father would stand in front of him.