MICROBIOME NEWS: Circumcision Appears to Alter The Penis Microbiome, Study Finds. “Some of the bacterial communities that shrank following circumcision have been linked to inflammation and sexually transmitted infections (STIs) in other research. That tentatively implies circumcision may reduce a person’s susceptibility to STIs by limiting inflammation in penile tissues and viral targets on the skin.”

I recall studies from the 80s indicating that heterosexual AIDS transmission was much lower in parts of Africa that practiced circumcision.