A new study by the U.S. Centers for Disease Control and Prevention (CDC) shows that birth rates in teenagers increased in 2006 and 2007 and that sexual and reproductive health in young people has been declining in recent years, ABC News reports.

In 2006, most new HIV cases among youth occurred among those between ages 20 and 24, according to 2002–2007 data from the CDC. In addition, syphilis cases increased in recent years among both young men and women ages 15 to 24.

The figures also reveal that an estimated 745,000 pregnancies occurred among girls younger than 20 in 2004. Teen birth rates had declined from 1991 to 2005.

Moreover, the study found a number of racial/ethnic disparities in the sexual and reproductive health of U.S. teens. For example, non-Hispanic black youth in all age groups have the highest rates of new HIV/AIDS diagnoses, and Hispanic women ages 15 to 19 are more likely to become pregnant than their black and white peers.

“It is disheartening that after years of improvement with respect to teen pregnancy and sexually transmitted diseases, we now see signs that progress is stalling and many of these trends are going in the wrong direction,” said Janet Collins, director of the CDC’s National Center for Chronic Disease Prevention and Health Promotion.