Are you having safe sex? If you answered “sometimes” or “I think so,” consider these scary statistics: The Centers for Disease Control and Prevention (CDC) estimates that nearly 20 million new cases of sexually transmitted diseases (STDs) occur each year in the United States, and one-half are among 15- to 24-year-olds. Shocked? It gets worse. According to the World Health Organization (WHO), more than 1 million sexually transmitted infections are acquired every day worldwide.