In the Gemara of Chullin, examined in the post Maharsha, two men were mentioned explicitly as righteous men; Rabbana Ukba and Rabbana Nehemiah. These two men were the sons of Rav’s daughter as it was stated: “And the Rabbis set their eyes upon Rabbana Ukba and Rabbana Nehemiah, the sons of Rav’s daughter. Raba said: These are the three princes of the nations who plead in Israel’s favor in every generation.” Not too much is known about these two sons besides their parents and the “special excellence” as described by Jacob Neusner. Also, we are uncertain who the third prince was, it could be their father Hanan or a reference to Rav himself.
While it seems that the original text in Chullin refers to Rabbana Ukba and Rabbana Nehemiah as men who were able to plead for Israel’s safety, and significance is linked to Rav. The Lamed Vavnick “gene” could have been passed down through lineage, which was something we saw through R’ Simeon bar Yochai and Elazar ben Simeon. One could assume the lineage was through a male child since up until now we have not heard of any women as part of the Lamed Vavnickim. But Jacob Neusner points out that Rav’s son Hiyya was merely a great teacher and Aibu was advised by Rav to go into business. While Rav could be concealing his children’s uniqueness, we have learned about his grandchildren’s special characteristics and therefore Rav has clearly chosen not to hide the Lamed Vavnickim. The Gemara in Chullin 95b also rules out Rav’s son-in-law Hanan:
Rav was once going to his son-in-law R. Hanan when he saw a ferry-boat coming towards him. Said he to himself: When the ferry-boat comes to meet one it is a good omen. As he came to the door he looked through the crack of the door and he saw the meat of an animal hanging up. He then knocked at the door and everybody came out to meet him, even the butchers too. Rav however did not take his eyes off [the meat] and said to them: ‘If that is how [you look after things], then you are giving my daughter’s children forbidden meat to eat’.