There are multiple sources for information on STD's on the Net, but the most centralized and authoritative starting point is at the United States Department of Health and Human Services Centers for Disease Control and Prevention (CDC). Their home page on sexually transmitted diseases will connect you with a lot of information.
I am not a medical doctor, research scientist, or any other kind of expert on these matters; but I decided to look at the latest information that people who do not want to contract an incurable STD should be aware of. Look at the sources yourself, draw your own conclusions, and see your doctor for personalized advice and treatment. It appears the least pernicious of the incurables is:
HPV, human papilloma virus: here are the CDC poop sheets in general, for both sexes, and for men. Poignant pointers from the poop sheets:
There is no general test for HPV that can tell a man or woman his or her “HPV status”. There is no clear health benefit to knowing if one has the virus—since it usually causes no health problems and goes away on its own.
HPV is not a sign that you or your partner has been unfaithful in the relationship. HPV can be silent in the body for many years before it is found on a test. She may have had HPV for many years, and there is no way to know when or from whom she got HPV.
Approximately 20 million people are currently infected with HPV. At least 50 percent of sexually active men and women acquire genital HPV infection at some point in their lives. By age 50, at least 80 percent of women will have acquired genital HPV infection.
Most people who have a genital HPV infection do not know they are infected. The virus lives in the skin or mucous membranes and usually causes no symptoms. Some people get visible genital warts, or have pre-cancerous changes in the cervix, vulva, anus, or penis.
Genital warts are diagnosed by visual inspection. Visible genital warts can be removed by medications the patient applies, or by treatments performed by a health care provider.
There is no "cure" for HPV infection, although in most women the infection goes away on its own. The treatments provided are directed to the changes in the skin or mucous membrane caused by HPV infection, such as warts and pre-cancerous changes in the cervix.
The next incurable STD is Herpes, caused by the herpes simplex virus, primarily type II, although it is possible to get a type I infection in the genital area. Here's the CDC home page for genital herpes and the fact sheet, from which I quote the following:
Between the late 1970s and the early 1990s, the number of Americans with genital herpes infection increased 30 percent. Genital HSV-2 infection is more common in women (approximately one out of four women) than in men (almost one out of five). This may be due to male-to-female transmissions being more likely than female-to-male transmission.
HSV-1 and HSV-2 can be found in and released from the sores that the viruses cause, but they also are released between outbreaks from skin that does not appear to be broken or to have a sore. Generally, a person can only get HSV-2 infection during sexual contact with someone who has a genital HSV-2 infection. Transmission can occur from an infected partner who does not have a visible sore and may not know that he or she is infected.
HSV-1 can cause genital herpes, but it more commonly causes infections of the mouth and lips, so-called "fever blisters." HSV-1 infection of the genitals can be caused by oral-genital or genital-genital contact with a person who has HSV-1 infection. Genital HSV-1 outbreaks recur less regularly than genital HSV-2 outbreaks.
There is no treatment that can cure herpes, but antiviral medications can shorten and prevent outbreaks during the period of time the person takes the medication. In addition, daily suppressive therapy for symptomatic herpes can reduce transmission to partners.
The surest way to avoid transmission of sexually transmitted diseases, including genital herpes, is to abstain from sexual contact, or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected.
Genital ulcer diseases can occur in both male and female genital areas that are covered or protected by a latex condom, as well as in areas that are not covered. Correct and consistent use of latex condoms can reduce the risk of genital herpes only when the infected area or site of potential exposure is protected. Since a condom may not cover all infected areas, even correct and consistent use of latex condoms cannot guarantee protection from genital herpes.
Persons with herpes should abstain from sexual activity with uninfected partners when lesions or other symptoms of herpes are present. It is important to know that even if a person does not have any symptoms he or she can still infect sex partners. Sex partners of infected persons should be advised that they may become infected. Sex partners can seek testing to determine if they are infected with HSV. A positive HSV-2 blood test most likely indicates a genital herpes infection.
Another good site is Herpes Diagnosis, which has a very informative article on the disease that has the funky pictures within and also has an article on the new blood tests that can tell type I from type II. A comprehensive article on both types of Herpes Simplex is on the eMedicine site at WebMD.
The next category are the Viral Hepatitis infections, liver diseases, with five strains now identified. Intravenous drug use is a very high risk factor in Hepatitis, but there is risk of sexual transmission as well.
Type A, HAV, according to the CDC fact sheet, "is usually spread from person to person by putting something in the mouth (even though it may look clean) that has been contaminated with the stool of a person with hepatitis A." Some kinds of sexual contact could obviously result in transmission. There is a vaccine for type A that is recommended for travelers to high-risk countries and for men who have sex with men. There is no chronic (long-term) infection, however; and one-third of Americans have evidence of past infection (immunity). There's more information in CDC's type A FAQ.
Type B, HBV, again according to the CDC fact sheet, is best protected against by vaccination, which has greatly reduced the infection rate. High risk factors for type B include multiple sex partners, men having sex with men, occupational needle sticks, sharing personal care items that might have blood on them (razors, toothbrushes), tattoing and body piercing, and others. Condoms are recommended, but their efficacy is unknown at type B prevention. Learn more from CDC's type B FAQ.
Type C, HCV, by CDC's fact sheet, has transmission methods similar to type B but with lower risk in the cases of people having sex with multiple partners and people having sex with an infected steady partner. "HCV can be spread by sex, but this is rare." See CDC's type C FAQ for more.
Type D is a defective virus that needs the hepatitis B virus to exist.
Type E is transmitted in much the same way as hepatitis A virus. Hepatitis E, however, does not occur often in the United States.
This post is getting overlong, so just go to the CDC HIV/AIDS start page for much information on that plague. Prevention is the key here. Go on, go get tested. Get that nagging doubt off your mind. Know that you're clean of HIV and whatever other STD's you're clean of. Brag about it.
UPDATE: AIDS testing recommended for most Americans: Government wants routine screening for all between ages 13 and 64.