A disease you can get from having sex with someone who has a sexually transmitted infection and is contagious. Can include Bacterial Vaginosis, Chlamydia, Gonorrhea, Hepatitis, Herpes, HIV/AIDS, Human Papillomavirus (HPV), Mycoplasma genitalium (Mgen), Pelvid Inflammatory Disease (PID), Syphilis, Trichomoniasis, Chancroid, Scabies, and more. Used to be referred to as STDs, but more recently, the D as in Disease has been replaced with an I for infection, although it’s a crap shoot whether they call it an STI or STD. If you are concerned you might have an STI and need more information, the Center for Disease Control website is very competent: www.cdc.gov/std/general/