With the New Year comes new resolutions. And if you’re a parent of a teenager, one of the resolutions that you hope your child will make, if not already, is a pledge to wait until marriage before having sex.

According to a new study, however, parents should not sit snugly when such a pledge has been made as virginity pledge takers are not more likely than other teens to delay sexual activity and actually more likely to have unprotected sex.

While teens who take virginity pledges do delay sexual activity until an average age of 21 (compared to about age 17 for the average American teen), the reason for the delay is more likely due to pledge takers' religious background and conservative views – not the pledge itself, claims a study published in the January 2009 issue of journal Pediatrics.

“The sexual behavior of virginity pledgers does not differ from that of closely matched nonpledgers, and pledgers are less likely to protect themselves from pregnancy and disease before marriage,” the researchers concluded.

“Virginity pledges may not affect sexual behavior but may decrease the likelihood of taking precautions during sex,” they added. “Clinicians should provide birth control information to all adolescents, especially virginity pledgers.”

For the study, a team of researchers led by Dr. Janet Rosenbaum of Johns Hopkins Bloomberg School of Public Health in Baltimore, Md., examined a nationally representative sample of middle and high school students who, when surveyed in 1995, were under 15 years of age and had never had sex or taken a virginity pledge.

So that the outcome differences between pledgers and matched nonpledgers could not be attributed to preexisting differences, the researchers created a group of nonpledgers with prepledge characteristics similar to pledgers – including similar views on religion, birth control and sex in general. Past studies compared self-selected virginity pledgers with the general population and attempted to adjust for the vast prepledge differences by using regression models.

Five years after the pledge, pledgers and matched nonpledgers were compared on self-reported sexual behaviors and positive test results for three common STDs as well as safe sex outside of marriage by use of birth control and condoms in the past year and at last sex.

What the researchers found was that five years after the pledge, 82 percent of pledgers denied having ever pledged. Furthermore, pledgers and matched nonpledgers did not differ in premarital sex, sexually transmitted diseases, and anal and oral sex variables.

The study also found that pledgers had 0.1 fewer past-year partners but did not differ in lifetime sexual partners and age of first sex. In addition, fewer pledgers than matched nonpledgers used birth control and condoms in the past year and birth control at last sex.

"There's been some speculation about whether teenagers were substituting oral or anal sex for vaginal sex and I found that wasn't so," commented Rosenbaum, according to Health magazine. "But I did uphold a previous finding that they are less likely to use birth control and drastically less likely in fact to use condoms – it's a ten percentage point difference."

Rosenbaum expressed her concerns about abstinence-only sex education programs that promote virginity pledges as they may also promote a negative view of condoms and birth control.

“Teens learn condoms don't protect you completely from human papillomavirus (HPV) and herpes, which is true, but they may not realize that they protect against all the fluid-based STDs," she told Health. "People end up thinking you may as well not bother using birth control or condoms."

Rosenbaum did note, however, that while conservative groups such as Focus on the Family are not ones to embrace a pro-contraceptive message, they and just about every organization are on the same page when it comes to one message.

"Parents should talk to their kids about their sex. It should not be single conversation, it should be a continued conversation at the moments that are teachable moments," she said. "Parents tend to hope that schools will take care of it; they can't, obviously."

Last year, a first-of-its-kind federal study startled some adolescent-health experts when it revealed that at least one in four teenage American girls has a sexually transmitted disease.

Researchers with the U.S. Centers for Disease Control and Prevention had found that the overall STD rate among the 838 girls in the study was 26 percent, which translates to more than 3 million girls nationwide.

Another groundbreaking research study released later in the year further suggested that pregnancy rates are much higher among teens who watch a lot of TV with sexual dialogue and behavior than among those who have tamer viewing tastes.

The study, released in the November 2008 issue of Pediatrics, found pregnancies to be twice as common among those who said they regularly watched shows such as "Sex and the City," "That '70s Show" and "Friends," compared with teens who said they hardly ever saw them.

According to the Guttmacher Institute, nearly half (46 percent) of all 15-19-year-olds in the United States have had sex at least once. Though only 13 percent of teens have ever had sex by age 15, by the time they reach age 19, seven in 10 teens are believed to have engaged in sexual intercourse.

Each year, almost 750,000 U.S. women aged 15-19 become pregnant and eleven percent of all U.S. births are to teens.