Pretty much everyone at some point during their youth was told you could catch one from a toilet seat.
Yet, as much as this misinformation about STIs does exist, there are also some strange - and disturbing - facts about how, in theory, you could get infected WITHOUT having sex.
Worryingly, these are places and objects we come into contact with every day.
The only good news, as Cosmopolitan points out, is the odds of catching an STI from any of the below are very slim.
There are two types of herpes: simplex type 1 (oral) and simplex type 2 (genital), both of which can be spread by direct contact.
So, someone with oral herpes could spread the virus by using lip balm near an infected area, or if they use it shortly after oral sex.
On the plus side, STIs tend not to live long on inanimate objects. Still, it's best not to share lip balm too readily.
If you like trying out tester lotions and potions at the beauty counter, then you might want to give those a wide berth too.
2. Someone's beard
Beards are definitely having a moment. The downside is they have the potential to be a breeding ground for germs, causing fungal infections and herpes (again).
They can even carry pubic lice. A very thick beard may also disguise symptoms of a skin issue, meaning it's very important to maintain good beard hygiene.
3. Having a bikini wax
In addition to being in no way enjoyable, if the beautician is remiss and double-dips the application stick, having a wax also comes with the risk of catching an STI.
In further bad news, research has shown the action of removing pubic hair can cause "deficits in the mucocutaneous barrier" - the skin's membrane - which makes it easier for viruses or bacteria to enter the body.
4. Using a tanning bed
Not only does the ultraviolet light used in tanning beds not kill off bacteria, but, over time and with enough exposure, the bacteria may even become resistant.
Plenty of nasties can thrive on a sunbed. These include Staphylococcus bacteria, faecal bacteria, the herpes virus and the human papillomavirus (HPV).
5. Getting a tattoo or piercing
Much like with waxing, this depends on the safety and hygiene practices of the person in charge.
While most shops and parlours take this very seriously, needles can easily carry Hepatitis B or C and HIV .
So it's important to do your research. I guess that from now on, we will never do those five things in a place that we're unsure of, right?