Nearly 150,000 American teenagers from 13 to 17 years old — or one out of every 137 — would identify as transgender if survey takers asked, according to an analysis of state and federal data that offers an answer to a question that has long eluded researchers.

The figure stands to inform the fierce debate over the rights of transgender youth, reignited on Wednesday by President Trump’s decision to rescind an Obama administration policy that protected the rights of students to use bathrooms corresponding to their gender identity. The estimate may also help lawmakers and advocates across the country better understand the populations they serve.

“We want to make sure that policy debates are informed by actual figures,” said Jody L. Herman, a scholar of public policy at the Williams Institute at the U.C.L.A. School of Law, where she and several co-authors published the estimate in a report last month.

That report, the latest in a series on transgender populations, included estimates of the transgender population in each state and in different age groups. In addition to an estimated 149,750 transgender teenagers nationwide, accounting for 0.7 percent of the population ages 13 to 17, Dr. Herman and her co-authors estimated that there are 1.4 million transgender adults in the United States. In the younger age group, transgender identification is probably more common among the older teenagers than the younger ones, they said.