In 2014, researchers published results from the Contraceptive CHOICE project, a study of more than 9,000 women, more than 4,000 of whom were 14 to 24, who were at risk of an unplanned pregnancy. They were given long-acting reversible contraception at no cost, and followed for two to three years to see what would happen. The number of women who reported recent multiple sexual partners went down, not up. There were no increases in the rates of sexually transmitted infections.

Further, if we can get beyond a war of handpicked studies, we can look at what has happened in the real world. The proportion of teenagers who “ever had sex” dropped to 41 percent in 2015 from 47 percent in 2011. The proportion who were “currently sexually active” dropped to 30 percent from nearly 34 percent. The proportion who “had sexual intercourse with four or more persons” dropped to less than 12 percent from 15 percent.

The percentage of those using long-acting birth control, however, has been increasing. “There is no evidence that contraception increases high-risk sexual behavior,” Dr. Jeffrey Peipert, chairman of the Department of Obstetrics and Gynecology at the Indiana University School of Medicine and author of the study, told me.

Of course, disparities exist in family planning as in almost any aspect of health care. A 2016 study in The New England Journal of Medicine showed that the unintended pregnancy rate among women who earn less than the federal poverty line was two to three times the national average in 2011. An earlier study showed that in the years before, that rate was up to five times higher.

Effective, long-acting birth control can be expensive. First-dollar coverage, or coverage without co-pays or deductibles, was what the Affordable Care Act required, a requirement the Trump administration’s new rule undoes. Such coverage can offer women who don’t have upward of $1,000 of disposable income options that they otherwise wouldn’t have. The proportion of women who had to pay out of pocket dropped from more than 20 percent before Obamacare to fewer than 4 percent in 2014. Women saved more than $1.4 billion in 2013 because of this change.

“From a societal perspective, contraception saves health care dollars,” Dr. Peipert said. “Every dollar of public funding invested in family planning saves taxpayers at least $3.74 in pregnancy-related costs. It seems clear that providing contraception is a cost-saving preventive service and benefits public health.”