Many of us have heard these saying before and may have even believed them before we knew better. In fact, some people still believe these folk wisdoms even though all of the above are false.

Virgins are always clean.
You can be born with STDs. Also, not all STDs come from sex. more on that in a bit,

You can't catch STDs if you have only had sex with the one you lost your virginity to.
See the part about virgins.

If they look clean, they are clean.
Not all STDs have obvious symptoms. Some can go into "hiding" but still be transmitted. Herpes is the most famous for this, but HIV, AIDS, gonorrhea, syphilis, HPV and more can all have hidden or no symptoms.

If they say they've been tested, they have been tested.
People will say anything to get into your pants. This means they can lie because they think they're clean and don't need to be tested due to other things on the list.

STIs only come from sex or needle drugs.
Some STDs can be caught nonsexually. Hepatitis can come from undercooked meat, wearing pants that are too tight can cause vaginosis and sharing dildos can spread illness. There are more where that came from, too! The risk of catching an STI nonsexually without drug use is low, but it does happen.

It's very possible to be born with an STI as well. Since not all of them have symptoms and not all parents get tested, it's impossible to know unless you get tested.

Smokers have a special danger: if the mouthpiece burns the lips at all blood can get on their pipe. If said pipe is shared, you can catch blood borne diseases. Crack and meth users have this problem frequently.

All STDs have symptoms.
Not all STDs have symptoms all the time. See "If they look clean" for more.

Being part of an awareness group is as good as being tested.
Only testing is a substitute for testing. All people, clean or not, can be in awareness groups. less