STDs, particularly herpes, chlamydia, and gonorrhea, are transmissible via oral-genital contact. The precise risk is hard to quantify. Herpes may be transmitted when asymptomatic. About 12% of Americans have genital herpes. Women may be relatively asymptomatic with genital chlamydia. However, "oral" chlamydia usually causes significant sore throat. The CDC reports a case rate for chlamydia (in 2019) of 0.7% for women and 0.4% for men. Gonorrhea is about 1/10th as common as chlamydia. Gonorrhea infection is almost always quite obvious to both men and women.