The number of teenage girls suffering from a sexually transmitted disease is on the rise.

When it comes to parenting her teenage daughter, Esther Leos doesn't leave anything to chance.

“As mothers, I think that we have a responsibility to teach our girls about this so they won't be sexually active until they're ready, and to me, it’s until they’re married,” Leos.

According to the Centers for Disease Control and Prevention, at least one in four teenage girls in the U.S. between the ages of 14 and 19 has at lease one of the most common sexually transmitted diseases -- either the human papillomavirus (HPV), chlamydia, herpes simplex virus and trichomoniasis.

“It does concern me,” said Leos.

While it's a concern for many parents, Priscilla Leos, 15, says she's not surprised.

“I have a lot of friends and stuff that are sexually active and a lot of girls at my school are pregnant already,” she said.

HPV is the most common. It affected close to 20 percent of the teenage girls studied.

“I think what we're seeing with regard to sexually transmitted diseases is an epidemic,” said Gary Rose, an internist and the president and CEO of the Medical Institute for Sexual Health. He attributes the upward trend to an "over-sexualized" culture.

“Another problem is that generally, people think that if they use a condom, that they're 'protected' and having 'safe sex,' but we know that for some of these diseases like gonorrhea and syphilis, using a condom only lowers your risk by about 50 percent,” said Dr. Rose.

Some STDs can lead to infertility and cervical cancer, and they often have no symptoms.

“I don't think they understand the severity of what it can do to your body,” said Morgan Wortham, 16.

“I think girls are pressure into things a lot of times when they don't really know what the consequences would be,” said Whitney Wortham, 15.

HPV is the only STD that can be prevented by a vaccine.