You know your body better than anyone, so it seems obvious that you'd know if you had an sexually transmitted infection (STI) , right? Jenelle Pierce, executive director of The STI Project, begs to differ.

"The most common symptom of all STIs is no symptom at all," Pierce said. "So, regardless of gender, it's very common to have an infection and have no noticeable signs or symptoms of infection, which means, the only way to know is to get tested."

Most people blow off their need to receive consistent tests, instead believing in what Pierce calls a major misconception: "Only certain types of people contract STIs, and many people assume they're not one of them."

However, these infections don't discriminate. A 2008 estimate published in the journal Sexually Transmitted Diseases placed the number of Americans with an STD at 110 million, more than a third of the American population at the time. Researchers particularly noted the prevalence of human papillomavirus (HPV), a typically asymptomatic disease.