SIU School of Medicine

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Division of General Internal Medicine

Sexual Behavior

Unprotected sex and having sex with multiple partners place people at increased risk for sexually transmitted diseases and pregnancy. The following statistics show that young people are most at risk for these problems BUT remember that age alone does not protect you from problems. These diseases can and do happen in sexually active older people.

There are 15 million new cases of sexually transmitted diseases (STD’s) in the US each year. One fourth of these are among teenagers. On the other hand, one tenth of the people diagnosed with AIDS are over age 50.

In a 2003 survey by the Center for Disease Control, 47% of high school students reported that they had ever had sex. 14% of high school students had 4 or more sex partners in their life. 37% of sexually active high school students did not use a condom at last sexual intercourse.

Health Issues Related to Sex


900,000 adolescents under the age of 19 become pregnant each year. These pregnancies are associated with an increased risk of adverse health and social consequences for both mother and child.

Adult women are also at risk for unintended pregnancy if they do not take precautions. Pregnancy is still possible until your doctor says you are past menopause.


The most effective way to prevent pregnancy is not to have sex. This is called abstinence. Couples who do have sex need to use birth control properly and use it every time they have sex to prevent pregnancy.

There are many options available ranging from long acting injections and oral contraceptive pills to condoms. Please talk to your doctor about the method that would be best for you.

Sexually Transmitted Diseases

There are many forms of sexually transmitted diseases. This includes infections like AIDS, gonorrhea, chlamydia, pelvic inflammatory disease and several others. This section will only discuss a few of them. Please refer to the references at the end of the section for more information or ask your doctor.


What is HIV?
HIV stands for Human Immunodeficiency Virus. This virus damages the immune system and eventually causes AIDS.

How does someone get HIV?

  • Blood, semen, and vaginal fluid carry the AIDS virus (HIV). To transmit the virus, blood, semen or vaginal fluid must pass directly from an infected person into another person’s body. Having sex without condoms passes the virus from one person to another.
  • Sharing IV drug needles also spreads the virus. The virus lives in small amounts of blood left in an unclean needle.
  • An infected woman can pass the virus to her unborn baby while she is pregnant or during birth. A nursing mother can pass it to her newborn baby while breastfeeding.

You CAN’T get HIV/AIDS from:

  • Kissing or hugging.
  • Touching. You can’t get HIV by touching or being near someone who is HIV infected or who has AIDS.
  • Eating. You can’t get HIV by eating with someone who has HIV or AIDS or by being served food by an HIV infected person.
  • Sneezing or coughing
  • Clothing or bedding
  • Mosquito bites

How will I know if I am infected with HIV?

You can take a blood test that shows if you have been infected with the virus. It is called the HIV or AIDS antibody test. If you are infected with the virus, you will test positive. Even if you feel fine, you can pass the virus on to someone else.

If you test negative, you may not be infected or it may be too soon to tell if you are carrying the virus. The test checks to see if you have produced antibodies to HIV. Most people form antibodies three to six months after they were exposed to the virus.

If you would like to be tested, you could ask your doctor to order the test for you. There is also a home test kit available. You buy the kit, follow the directions to obtain a sample and send it back to the company. The home kit is approved by the FDA and the results are kept confidential. The home kit costs about $50 and results are available in about 1 week

Specialized care for patients with AIDS is available through our Division of Infectious Diseases.

How can I protect myself and my partner?

You can’t tell if someone has the virus by how they look. If you are going to have sex, here are some safe sex guidelines:

  • Always use a latex condom for vaginal, oral or anal sex.
  • Don’t get semen or vaginal fluids in your mouth.
  • Nonoxynol-9 is a spermicide that kills the virus. Always use a spermicide with a condom; never use it alone.
  • Don’t use Vaseline, vegetable or mineral oil with condoms. They make condoms break more easily. Use water-based lubricants like K-Y jelly.
  • Always leave some room at the tip of the condom to catch the sperm. This will keep the condom from breaking.
  • Throw the condom away after using it. Never use the same condom twice.
  • Use a latex square (dental dam) or plastic wrap for oral sex with a woman. Vaginal fluid and menstrual blood can carry the virus.

Hepatitis C

What is Hepatitis C?

Hepatitis C is a viral infection that affects the liver. It can lead to chronic infection which can result in cirrhosis and hepatocellular cancer. Hepatitis C Virus may accelerate liver damage in people who drink alcohol excessively.

How does someone get infected with Hepatitis C virus (HCV)?

  • Blood transfusion. HCV can be transmitted by blood or blood product transfusion. This was much more common prior to 1990 when the test for HCV became available. Current donor screening and testing has almost eliminated transmission of the virus by this route. The chance of becoming infected with HCV from a transfusion is estimated at 1 in 100,000.
  • IV drug use. Over 60% of new infections with HCV occur in patients who have injected drugs in the previous 6 months.
  • Nasal cocaine use. This may be due to blood on shared straws.
  • Needle stick accidents. Healthcare workers are at risk if they are accidentally stuck with a needle from a HCV-positive patient.
  • Possibly by tattooing and body piercing.
  • Sexual transmission. Sexual transmission can occur but the risk is extremely low. The risk is increased for persons having multiple sex partners.
  • Perinatal transmission. A mother who is infected with the Hepatitis C virus can pass the infection to her child during birth.

How can I know if I am infected with HCV?

There is blood test available to check for HCV. You should ask your doctor about it if you think you are at risk.

General Information about your health

Sexuality in later life
NIA Information Center

Resources for adolescents

Information about HIV home test kits: