Diseases which spread through sexual contact are referred to as "Sexually Transmitted Diseases" or STDs.
As Everett Koop, MD, Former US General Surgeon put it "When you have sex with someone, you are having sex with everyone they have had sex with for the last ten years, and everyone they and their partners have had sex with for the last ten years.
" Here are some facts about STDs:

• Although STDs affect men and women, the health problems caused due to STDs might be more severe for women.
  
• The main causes of STDs are bacteria, parasites and viruses.
  
• Chlamydial Infection is the most common of all bacterial STDs and it might lead to pelvic inflammatory disease (PID) in women.
  
• Gonorrhea is one of the most commonly reported infectious diseases in the United States.
  
• The very first signs of HIV infection may be flu-like symptoms and swollen glands, which might appear within a month or two.
  Severe symptoms might take years to appear.
  
• People who have been infected can survive for many years with medication to fight the HIV infection.
  
• STDs may cause cervical and other cancers, pelvic inflammatory disease, chronic hepatitis and infertility in women.
  
• The risk of acquiring STD is high among youngsters who indulge in sexual activity and increases when an individual has multiple sex partners.
  
• Individuals who are infected with STDs are more likely to acquire HIV infection when exposed to the virus through sexual contact than uninfected individuals.
  

A number of intervention studies have revealed that detection and treatment of STDs might decrease transmission of the HIV virus.
There are a number of websites which offer helpful information on STDs.
You can also visit a clinic to get yourself tested for HIV.