There is a well-known story, that when Rabbi Shimon Schwab left the Mir Yeshiva to become a Rav in Germany, he went to the Chofetz Chaim and spent a Shabbos in Radin. In one of their conversations, the Chofetz Chaim asked him: “Why is it that am I a kohen and you are not?” Rabbi Schwab understood that the Chofetz Chaim had a lesson to teach him and waited for the CHOFETZ CHAIM to explain. The Chofetz Chayim said to him “when Moshe Rabbeinu said to Bnei Yisrael ‘mi l’Hashem elai’ – ‘Who is willing to stand by me for the honor of Hashem?’ – my grandfather came forward and your grandfather did not!” The CHOFETZ CHAIM implored him that this situation may arise again, and that he should not make the mistake of his grandfather. When there is a rally call to come forward for Hashem’s honor – make sure that you are there.
The question is, is it really true that just because someone’s grandfather did something it can change the genetic makeup for all the following generations? The answer to the question is: yes. There are things that can happen in our lives that can actually be transferred from generation to generation. We see examples of this throughout Chazal: (Yevamos 79A) The signs that one is a member of klal Yisrael is that he posses the middos of mercy, shame, and chesed. The Maharal in Nesivos Olam (Bushah Siman Aleph) says that we inherited all of these middos from the toil that the Avos put into them. Sometimes there can be an act so great that it affects not only us but also our offspring. The Ruach Chaim on Pirkei Avos (5:3) says that the reason why some Jews will have the courage to suddenly come to Eretz Yisrael, despite the difficulties, comes from the genes of Avraham Avinu, who laid the path out for us.
Rashi tells us that the Shevet of Levi was counted from the time that they were 30 days old, whereas the rest of klal Yisrael was only counted from the age of 20 years. Not only that, Rashi (3:15) says that they are already called a “Guardian of the charge of the Sanctuary” from that age. How could a 30 day old baby be called a guardian? At age 20, a person becomes a full adult, mature and ready to perform the tasks set out for him for his life’s mission (This is probably why we only start to receive punishments from age 20). Until that time he is not mature enough to be ‘counted on’. Whereas, the ability of the tribe of Levi to guard and care for religious rites is actually an inborn trait. It seems that the CHOFETZ CHAIM taught us (through Rav Schwaab) that though sometimes we don’t necessarily have the natural disposition to achieve greatness, nevertheless, just like I am a Kohein through the work of my grandfather, you can actually become a Levi as well!
As history has shown, Rabbi Schwab indeed rose to the task and became one of the guardians of our faith. It seems to me that we all have the ability within us to create a new family gene.