According to their 2008 Sexually Transmitted Disease Report, the Center for Disease Control found that there were more than 1.5 million total cases of chlamydia and gonorrhea reported— making them the two most commonly reported notifiable infectious diseases in the United States. Bear in mind also, that in the case of Chlamydia, most of the people who have it don't even realize they have it, so the actual numbers are probably greatly under reported.
Additionally, adolescent girls and young women are especially hard hit by these two diseases. The largest number of reported cases of both chlamydia and gonorrhea in 2008 was among girls between 15 and 19 years of age, followed closely by young women 20 to 24 years of age. This likely reflects a combination of factors, including biological differences that place females at greater risk for STDs than males, as well as higher STD screening rates among young women.
Check this video for more interesting facts about Chlamydia:

So, if found in a reasonable time frame, Chlamydia is relatively easily treated. If untreated, it can lead to sterility in men, and potential chronic damage to the reproductive health in women, even potentially leading to death in certain cases or possible spread to child during birth. Uuugh!
Avoid it by correctly using condoms, and make sure you get tested annually.
If you have questions, call these guys. Not only are they real nice, but they give you a free doctor consultation. And it's all confidential.

