Yes, it is true. Symtoms can lay dormant in your system for months or even years. HPV, Herpes, and Syphilis (yes, it's comming back) are the ones to most be concerned with. Syphilis can lay dormant in your system for year and years before any symptoms appear. HPV is another story. HPV can lay dormant for up to 2 years. There are hundreds of strands of HPV. Some strands men will never develope but they are carriers and can pass it to female partners causing cervical dysplasia and can even cause cervical cancer. Other strands which both male and females can get cause actual warts. I'm not sure about the time spand with Herpes but with herpes and hpv, they never go away. Ever, so protect yourself and don't be one of the 80% of hpv carriers. Yes, 80% of the sexually active people in the world carry a strand of hpv. Be safe and best wishes!