during the lineage of the family of Levi, it says "These are the generations (children) of Aharon and Moshe..." and it goes on to list the children of Aharon, and not the children of Moshe.
Rashi tells us that we learn from the fact that it calls the children of Aharon as being also the children of Moshe that one who teaches someone else Torah, it is as if that person is his child. So the children of Aharon were also the children of Moshe, because Moshe taught them Torah.
That is very nice, but what about the actual children of Moshe? Why do they not get mentioned at all? It is listing the children of all the Levite families, so why not list Moshe's children as well?
We did not have an answer for this. I saw one answer about how Moshe's children had stayed behind with Yisro in Midian. I do nto remember why, but I did not like that answer, as they are still Moshe's children and should have been mentioned...