A new study has been released about teenage sexuality. Unlike many studies I have seen, this one was actually peer reviewed. It was published in the current edition of Adolescent and Family Health. I don't know much about this outfit so I cannot speak to their biases. However, I know a fair amount about scientific research and I have read their paper.

They use secondary data (data already collected). The data came from the U.S. Government (the National Center for Health Statistics) and the research arm of Planned Parenthood (the Alan Guttmacher Institute). So their data is either unbiased or biased toward a Planned Parenthood goal. Their conclusion is all the more powerful as it refutes an earlier AGI study.

The earlier AGI study concluded that 25 percent of the decline in the teen pregnancy rate has been due to abstinence and 75 percent to the increased use of more effective contraception. You may have seen these numbers in various media articles.

The new study used more sophisticated research methods to better examine the data. For example, the AGI counted non-virgin teenage girls who had not had sex in at least a year who did not become pregnant - naturally - as those who were "at risk for pregnancy." This obviously artificially inflated the effectiveness of the contraception methods. Once this mistake (or deliberate deception) was fixed, the birthrate among sexually active teenagers actually increased! The overwhelming majority of the decline in the US teenage birthrate can be explained by abstinence. Abstinence accounted for 67% of the decline among single teenage girls.

If you would like more details, an analysis is available here. It is written for the layperson. If you enjoy research, the actual report can be downloaded here.