I can't count the number of times that a patient was shocked when they were diagnosed with an STD. Many of my patients seem surprised that their sexual partner gave them an STD. Though they won't admit it, they probably assumed their partner was clean based on simple questioning or on poor judgment.

That is a huge mistake.

STDs are spread largely because people don't know that they have them. For example, 2/3 of women and ½ of men with Chlamydia infection DON'T know they're infected...