Social Transmission
People who live together, touch, share food or share air also share bacteria. Household members, partners and even pets converge on more similar microbial communities over time.
The human parallel
The people you spend time with change you — measurably, at the level of which organisms live in your body.
Why it matters
Your microbial community is partly a social fact, not just a personal one. Relationships have a biological footprint.
What we can say
Each claim carries a confidence rating, a caveat, and the papers it rests on.