One of the funniest moments in Toy Story 3 was when Woody surreptitiously placed a sheet of paper on a public toilet seat in the midst of a daring escape. It was funny because it was relatable. But are public toilet seats actually any dirtier than the ones in your house? The answer's in the headline.
Women's issues website Broadly recently asked this very questions to Dr Nilka Figueroa, an Infectious Diseases Chief Fellow at Harlem Hospital Center in the US. According to Dr Figueroa, it's virtually impossible for infectious agents to be transmitted via a shared toilet seat:
In most public restroom surfaces, human-associated bacteria dominate. This bacteria are skin microbes that most people already have, so they pose almost no risk of infection.
Apparently, this includes urine droplets on the seat. While these are unquestionably gross, they do not pose a significant threat to your health as contamination through the butt is basically impossible. To contract a urinary tract infection, your urethra - the tube that connects your bladder to your genitals - would need to touch the seat. (Nevertheless, I'll still be moving to another stall in these situations.)
The same goes for STIs, which can't survive for long after leaving the human body and require an opening for infection to take place. If you have a scratch on your butt, you'll obviously want to exert more caution. But even then, picking up a disease is extremely unlikely.
Naturally, it's still very important to wash your hands with soap after visiting the loo. As Figueroa notes, this is the most effective way to avoid illnesses from bacteria, whether it's from a public toilet or your own. It's also a good idea to avoid touching your face until you wash your hands and to dry them thoroughly after washing.
Still not convinced? You can read the full story with further insights from Dr Figueroa here.