There is a connection between the microbiome and owning pets.

Research shows that people who live with dogs have more diverse microbiomes in comparison to non-pet owners.

Children with pets have fewer allergies than non-pet owners.

Why is this?

Animals have biodiversity in their own microbiome and they introduce different microbes into our human microbiome, which help to diversify our microbiome by living with these pets. Pets also play in the dirt, soil and bring that into our homes and that also helps to diversify our microbiome.

Reference:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6003855/