When you enter a public bathroom and, on the wall, you see a dispenser filled with toilet seat covers…do you take one of them?

Hamlet was wrong. To cover or not to cover—that is the question!

On the one hand, there’s an undeniable “ick factor” when it comes to sitting on top of something that countless bare-butted strangers have sat on before you—especially if you spot bits of water, urine or (worst of all) feces on the seat. So part of you is probably eager to do whatever you can to shield yourself from germs and avoid getting yourself wet and/or soiled.

But on the other hand, seat covers are generally made of porous tissue paper that is laughably thin. They have to be that thin, or they might clog toilets. And don’t let the waxiness of the paper fool you—if there is liquid on the seat, it is likely to bleed through the cover. So another part of you is probably thinking, How protective can these covers truly be? And even if a germ does touch me, could I really get a disease that way?

We asked Charles Gerba, PhD, a professor of environmental microbiology at The University of Arizona in Tucson—widely known as “Dr. Germ”—for his extensive research about bacteria and organisms covering public surfaces.

THE MUCK OF THE MATTER

In essence, here’s what he said: “I don’t know of any scientific data on this specific topic, but based on my past germ research, in my opinion, most toilet seat covers are useless,” he said.

What sort of germs might you find on a toilet seat? If you’ve bought into the common misconception that toilet seats carry sexually transmitted diseases (STDs), you’ve been fooled. The organisms that cause STDs, such as the viruses that cause herpes and AIDS and the bacteria that cause gonorrhea and syphilis, can’t survive on cold, hard toilet seats for more than a few minutes, Dr. Gerba said. So by the time someone leaves a stall and you’re ready to sit on the toilet, odds are, those types of germs are dead.

Other germs can survive on a toilet seat indefinitely, though—such as fecal bacteria (including E. coli) and the MRSA bacterium (methicillin-resistant Staphylococcus aureus), which can be transferred from a person’s skin to the toilet seat.

But how, exactly, would those types of germs infect you? “I suppose it’s physiologically possible, but the chances of it happening are very, very slim,” said Dr. Gerba.

For example, one way for fecal bacteria to be transmitted to your body would be for you to have an open sore—but you’d have to have an open sore on your buttocks or the back of your thighs in the specific place where the germ happens to be situated on the toilet seat. Another way would be by doing a poor wiping job—as you move a wad of toilet paper toward yourself, you accidentally brush by the toilet seat (collecting the germ) and then accidentally let the toilet paper touch your urethra. A third way? Perhaps you accidentally touch the toilet seat with your bare hands…don’t wash your hands properly with soap and warm water after you finish going to the bathroom…and then later touch your nose or mouth and ingest the germ.

MRSA is a little more concerning, because research has shown that it can spread from simple skin-to-skin contact (as opposed to through a bodily opening), but Dr. Gerba said that even though it has been found on toilet seats in hospitals, there is no direct evidence proving that anyone has ever contracted MRSA by sitting on a toilet seat.

So, again, is it possible to get infected by a germ from putting your bare buns on a toilet seat? “Theoretically, yes, but realistically, no,” said Dr. Gerba.

Even if the risk for infection were high, how much protection would a toilet seat cover provide? Dr. Gerba said that a toilet seat cover is likely to provide protection only if it’s not porous—so the only ones likely to protect you are those nonporous plastic covers that rotate around the seat before a new person sits down (the bathrooms in Yankee Stadium in New York City, for example, have these, as well those in the Louis Armstrong New Orleans International Airport in Louisiana).

WORRY ABOUT YOUR KITCHEN, NOT YOUR BATHROOM

According to research, far more dangerous germs exist on kitchen surfaces, such as sinks and counters, than on toilet seats, whether in public or at home. E. coli bacteria, for example, are 200 times more prevalent on cutting boards than toilet seats, he said. “It’s actually safer to make a sandwich on a typical toilet seat than a typical cutting board,” he said.