Thanks for your question. Because HSV 1 usually causes cold sores, it is usually passed from person to person by kissing. It can also spread from the mouth to the genitals during oral sex. If this happens, it causes genital herpes - or herpes in the genital area. If a person HAS genital herpes due to HSV 1 , it can also be transmitted during sexual intercourse.
HSV 2 is usually transmitted by vaginal or anal sex. Theoretically, HSV2 can pass from a person's genitals to a partner's mouth during receptive oral sex causing oral herpes, but that is not commonly seen. Experts aren't sure why. For more information on transmitting Herpes 1 or 2, please read Dr. Grayson's article by clicking on the following link: Transmitting Herpes: How To Protect The Ones You Love