What is chlamydia? Chlamydia is a bacterial infection. It is one of the most common s*xually transmitted diseases in the United States. This infection spreads easily because it is often asymptomatic. This means that you can transmit chlamydia to your s*xual partners without knowing it. Among people with chlamydia, approximately 75% of people with vaginas and 50% of people with penises do not...