Most people know about sexually transmitted diseases, or STDs. Many kids learn about them in school, and people of a certain age remember the fear of AIDS in the '80s and '90s all too well. However, even armed with this knowledge, the prevalence of STDs is higher than ever, according to the journal Sexually Transmitted Diseases. Nearly 20 million people contract a sexually transmitted disease every year, and half of those are in people aged 15 to 24. A whopping 110 million Americans have an STD. The Centers for Disease Control and Prevention included eight STDs in the analysis: chlamydia, gonorrhea, hepatitis B virus (HBV), herpes simplex virus type 2 (HSV-2), HIV, human papilloma virus (HPV, also known as genital warts), syphilis and trichomoniasis. So why are so many people throwing caution to the wind? It may be due to the misperception that most STDs are treatable, cause no complications and aren't worth worrying about in the heat of the moment. Many young people today believe people simply don't die of AIDS anymore, which simply isn't true.