**1. Introduction**

Sexually transmitted diseases (STDs) disproportionately affect young people, with more than half of the infections occurring in 15- to 25-year-olds, although as an age group they constitute only 25% of the sexually active population [1]. Family physicians and pediatricians must be familiar with the context around STDs and mainly with the key clinical elements for diagnostic suspicion, always evaluating sexual abuse. More than 1 million sexually transmitted infections (STIs) occur every day and an estimated 376 million chlamydia, gonorrhea, syphilis, and trichomoniasis infections occur each year. STIs can have serious consequences beyond the immediate infection itself, through mother-to-child transmission of infections or conditions such as infertility and cervical cancer and some STIs can increase the risk of HIV acquisition three-fold or more. Adolescents have been considered as a key, vulnerable and marginalized population (i.e., poor access to adequate health

services, social and parental acceptance, stigmatization, among others) [2]. In this chapter, we will be describing the major clinical features of Gonorrhea, Chlamydia Trachomatis, and Genital Herpes.
