A new study shows the mix of bacteria in saliva is most influenced by the surroundings of the person, including human relationships.
The study reported that spouses, parents and children younger than 10 living in a household together had the most similar saliva microbiomes. This is due to both intimate contact and general environmental conditions. Children younger than 10 had more similar bacteria to their parents than older children, perhaps reflecting that older children are becoming more independent individuals.
The study discovered that a person’s genetics played virtually no role in shaping their saliva microbes.
So, the old saying “my father had bad teeth” is true — not because of DNA, but because saliva was shared one way or another with Dad likely at an early age.