My dad as a pediatrician and internal specialist would always wince when bleach brands like Clorox would advertise that they were safe enough to clean baby toys. He told me that this type of extreme sterilizing of baby toys gives them less exposure to harmless bacteria which could build the baby’s immune system and protect them from diseases. One study found that there may be a correlation between exposure to everyday bacteria and a baby’s health.

This study aimed to see if exposure to bacteria from the parents cleaning the pacifier by sucking it not rinsing or boiling it increased the baby’s health. 184 infants were studied while their parents had to maintain a daily diary about food intake and significant events and doctors frequently checked on them. At 4 months old the babies were studied for saliva samples, and at 6 months old parents were interviewed for their methods when it came to cleaning their pacifiers. Out of this group of babies that were studied from birth, 65 had parents that would clean the pacifiers by sucking. This same group had less chances of eczema, allergies, and asthma, as well as possibly altered microbes in the mouth seen through the saliva samples. This seems to support the correlation that an increased exposure to bacteria strengthens an immune system compared to those who fastidiously clean.

While the data does seem to support the hypothesis, there could be certain things to consider. For example, there could be third factors. As Dr. William Schaffner said in a New York Times article (even though he did not conduct the study), “It’s a very interesting study that adds to this idea that a certain kind of interaction with the microbial environment is actually a good thing for infants and children…I wonder if the parents that cleaned the pacifiers orally were just more accepting of the old saying that you’ve got to eat a peck of dirt. Maybe they just had a less ‘disinfected’ environment in their homes.” Also, if the babies were born prematurely or were sickly, it could affect how healthy the babies are regardless of the exposure to the bacteria. This plays into the idea of reverse causation: what if the babies who were born with stronger immune systems could handle the bacteria better? Yet because of first principles – the parents sucking/boiling the pacifier and then the consequential health results – this seems unlikely.

Maybe I’m biased towards my own father’s opinion, but I don’t think that this is a bad idea to consider for down the road when raising children of my own. If it’s the principles my dad used to raise me, why not? I don’t think I turned out too terribly.