http://www.siecus.org/pubs/fact/fact0019.html
Sexuality Information and Education Council of the United States
There are more than 25 diseases spread primarily by sexual activity. This fact sheet provides basic information about eight of these infections-called sexually transmitted diseases (STDs). It focuses on the most common STDs and contains information on how they are spread, what signs and symptoms individuals should look for, and what treatment options are available.