Chlamydia

The most common STD and a common cause of sterility! About one in every 10 teenage girls has it! It's an infection of a bacteria-like organism called chlamydia trachomatis. If left untreated in women, chlamydia can infect the cervix, cause scarring of the fallopian tubes, cause sterility and lead to pelvic inflammatory disease. It can also be passed to an infant in the form of an eye infection or pneumonia. If left untreated in men, it can infect the urethra, spermatic cord, epididymis and prostate and cause sterility.

Methods of contraction

Vaginal intercourse: most common method
Anal intercourse
Oral sex

High risk groups

Sexually active teenagers ages 15 to 19

Symptoms

75% of Chlamydia carriers exhibit no symptoms at all. If symptoms do occur, they'll show up 2 to 3 weeks after exposure.

Males (more likely to exhibit symptoms)

A mild to painful burning sensation during urination
A clear or pus-like discharge from the urethra of the penis especially in the morning
Pain in the testes

Women

A vaginal discharge coming from the cervix, which might be difficult to differentiate from a normal vaginal discharge. If you notice mild bleeding after a gynecology exam or sex and are sexually active, consult your physician.

Women usually don't exhibit symptoms and thus aren't aware they have it, unless they ask their doctor to check for it.

Diagnosis

A pelvic examination of the cervix
A urine test
Treatment
Prescribed antibiotics
The infection should disappear within 1 or 2 weeks.
Tell all your sexual partners so they can be treated. This will prevent the possibility of reacquiring the infection.
Avoid touching your eyes after exposing your hands to infectious secretions, or you could give yourself an eye infection.