Advocates for unfettered access to the “morning-after pill” Plan B One-Step took their case to President Obama’s chief science adviser Friday, asking him to find out the basis for the administration’s controversial decision last month to continue requiring that young teens get the drug only by prescription.

In brief presentations wedged into a meeting of the President’s Council of Advisers on Science and Technology, five experts decried Health and Human Services Secretary Kathleen Sebelius’s rejection of the Food and Drug Administration’s move to make Plan B available over the counter.

“We are asking you to work with us . . . to readdress this decision, find out how it was made and why,” Wayne C. Shields told John P. Holdren, the chairman of the council. Shields is president of the Association of Reproductive Health Professionals, a trade organization with offices in Washington.

In her allotted two minutes of public comment, Francesca T. Grifo of the Union of Concerned Scientists quoted Sebelius’s Dec. 7 letter that rejected the FDA’s plan to make Plan B available to girls younger than 17 without a prescription.

“Secretary Sebelius used phrases like ‘based on my review’ and ‘my conclusion,’ ” Grifo said. “This is exactly the situation which scientific integrity policies are created to prevent: namely, a non-scientist, political appointee overturning a decades-long process of scientific research and review both inside and outside of the FDA.”

Afterward, however, she and the others said the issue didn’t involve “scientific integrity” as commonly understood.

“This not about fraud, not about misconduct.” Shields said. “It is about standing up to the stated principles.”

As Obama’s adviser for science and technology, Holdren has no direct influence over either Sebelius or FDA Commissioner Margaret Hamburg. It’s unclear how Sebelius’s decision to keep some restrictions on Plan B access could be undone short of Obama ordering her to undo it. That action would probably be more controversial than Sebelius’s overruling of Hamburg.

Holdren told the speakers: “I will communicate the concerns that were expressed here to my boss.” He also addressed the issue of scientific integrity.

“What scientific integrity requires is that the clearest and most objective evidence be made available” to decision-makers, he said. “That does not necessarily guarantee that the scientific findings alone will determine the outcome.”

“Emergency contraception” — a dose of the hormone progesterone taken up to 72 hours after intercourse — has been controversial since it was first tested more than a decade ago.

Some opponents say it will encourage sexual activity by girls or make exploitation of them easier. Some view it as hazardous, although studies have shown it works and has no serious side effects. Some view it as an abortion pill, as it can prevent the implantation of a fertilized egg in the uterus.

The first formulation of Plan B was approved by the FDA in 1999. In 2004, the agency rejected an application to make it available without a prescription. In 2006, however, such availability was allowed for women 18 and older. In 2009, the age restriction was changed to 17 and older.

The drug is not “over the counter” in the sense that it can be picked off the shelf like a bottle of aspirin. The purchaser must show proof of age, and the drug can be handed over only by a pharmacist.

In its most recent application to the FDA, Plan B’s maker, Teva Women’s Health, was seeking to lift all restrictions, making the product easier to buy. The FDA told the company it had to conduct further studies on whether girls younger than 17 could take the drug properly.

“No product ever has had to do age-breakdowns like that,” said Susan F. Wood, an associate professor at George Washington University’s School of Public Health who in 2005 resigned her job as an assistant FDA commissioner in protest of the long delays in changing Plan B’s status.

Teva submitted more data last February. They included the results of two kinds of studies: a “label comprehension” study assessing whether girls as young as 11 understand the directions on the Plan B box, and an “actual use” study recording the experience of girls as young as 11 who used the drug to prevent pregnancy. But according to an article in the Journal of the American Medical Association last month, there were no 11- or 12-year-olds in the “actual use” study because none showed up at the clinics where the study was run.

In her letter overruling the FDA decision, Sebelius noted that some girls start menstruating at age 11 but that Teva’s studies “do not include data on all ages for which the drug would be approved.” She implied — although did not say outright — that the lack of data on 11-year-olds was the basis for her decision.

Experts in emergency contraception, however, say that because pregnancy in 11-year-olds is so rare it would be virtually impossible to ever get “actual use” data for that age group.