In this story:

• One in four affected
• Hidden virus goes untreated
• Related stories and sites

WASHINGTON (CNN) -- A new study shows that the United States has an "astronomical number" of new cases per year of sexually transmitted diseases, or STDs.

Experts say the study, done by the American Social Health Association and Kaiser Family Foundation, indicates it's time the nation confront the issue -- particularly because everyone who is sexually active is at risk.

"There are about 15 million new cases of STDs in the U.S. each year," said Linda Alexander of the American Social Health Association. "That's an astronomical number. It's one of the highest rates of all industrialized countries in the world."

The new figure represents about three million more cases a year than were detected in the 1980s, when detection for STDs was not as accurate.

According to the study, STDs affect one in four U.S. citizens over a lifetime. The risks associated with STDs range from sterility to cancer to death.

One in five Americans over age 12 has contracted genital herpes, according to the study. That's about 45 million reported cases.

The top STDs include four that can be treated with antibiotics: Chlamydia, gonorrhea, syphilis and trichomoniasis.

They also include viral infections that have no cure: genital herpes, genital warts (also known as human papilloma virus), hepatitis B and HIV, which causes AIDS.

"If you have a sexually transmitted disease, you're more likely to acquire HIV if you're exposed to it and you're more likely to transmit HIV if you have it," Alexander said.

Jimmy is brain damaged because his mother had genital herpes while she was pregnant with him

Some people can contract an STD and never see a symptom, which means the disease goes untreated and the patient continues spreading it.

When Barbara Wilkop got pregnant with her son Jimmy in the mid-1980s, she had no idea she had contracted genital herpes.

The hidden virus led to a premature delivery and her son suffered from encephalitis.

Now 11 years old, Jimmy has been left with the brain capacity of a three-year-old.

"The social stigma involved prevents people from going out and getting a diagnosis," Wilkop told CNN. "Being a nurse, having a college degree in nursing, I did not know that I had the disease."

Experts say a national discussion on the issue could help change social attitudes toward STDs.

Experts also say some major challenges must be overcome in order to beat back the high rate of STDs. Those challenges include getting doctors to talk about STDs with their patients and convincing both men and women to get tested and to use protection.

Correspondent Louise Schiavone contributed to this report.