created at: 2013-03-21At my son Carston’s bris I proudly announced that he had already completed his first mitzvah—or at least I hoped he had.

Shortly after he came into this world, Carston gave up some blood—cord blood. He didn’t really have to do anything, but hopefully his donation will help save a life (and we know that to save one life is to save the entire world).

Any expectant mom who reads a baby magazine or signs up for a newborn-related email list has seen the ads for cord-blood banking. For parents with large personal fortunes, private cord-blood banking can seem like good protection against possible misfortune. Given some family’s medical history, private cord-blood banking might even be important. But for most of us, a better investment in our children’s futures is to take the thousands of dollars required for private cord-blood banking and open a college savings account instead.

My husband and I decided against privately banking our son’s cord blood, but I couldn’t stop thinking about cord blood.

For several years, my husband and I have been members of the National Marrow Donor Program. My husband has been matched not once, but twice, to someone in need of a bone-marrow transplant. It’s rare to be matched even once, so I joke that he has “super bone marrow” (though he’s never been called on to actually donate). I thought my son might have some of his dad’s super bone marrow and hoped he could perhaps help someone in need. So my husband and I decided to donate Carston’s cord blood to a public bank.

Because the hospital where I delivered did not collect cord blood, I reached out to the Carolinas Cord Blood Bank, one of four public cord-blood banks. They sent me a kit: a box that I brought with me to the hospital when I went into labor. A family member FedExed everything back to the blood bank the day Carston was born, and two days later we went home, minus the box, but with our bundle of joy.

We’ll never know if Carston’s cord blood helped someone, though of course I hope it has—or will someday. But to me, part of the importance of the act is in not knowing the specific impact. Hopefully my son’s cord-blood donation is but the first mitzvah in the life of a little mensch.

Hilary Levey Friedman, Ph.D., is a Harvard sociologist and writer who studies childhood, competition and beauty. In January 2012 she became a mother; she loves her son for many reasons, but especially because he has let her sleep through the night since he was 4 weeks old!