Each year millions of teens get infected with sexually transmitted diseases. Now, a new smartphone app can help teens know about STD risk beforehand.

The new app lets users 'bump' their STD status. "If you happen to be out at a bar or a fraternity house or wherever, and you meet someone, you can then bump phones and exchange contact information and STD status," said Dr. Michael Nusbaum, the developer of MedXSafe, a feature of the new app called MedXCom, ABC News reported.

He added that the new app encourages people to go for regular STD checks. People who get a negative diagnosis can then ask their doctors to document their STD-negative status on the app.

"[Some] undetected and untreated STDs can increase a person's risk for HIV and cause other serious health consequences, such as infertility," Mary McFarlane, an acting chief in the Division of STD Prevention at the CDC, told ABC News. Using apps to encourage people to get regular checks for STDs can help prevent spread of the diseases.

However, there may be some drawbacks that include letting people falsely believe that they don't have the disease when in fact, they might have had an infection that hasn't been detected yet. Also, these apps may encourage risky sexual behaviors.

"It can take months for HIV to show up on a test. So you can test negative today, go out on Friday night and have sex, and then get retested later and find out that you had HIV all along," said Renee Williams, executive director of SAFE, a nonprofit organization dedicated to abstinence education, ABC News reported.

According to statistics from Centers for Disease Control and Prevention, nearly 50 percent of all teens in the U.S. report that they've had an intercourse. About half of the 19 million new STDs reported each year occur in people aged 15-24 years.