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.
The Williams Institute, well regarded for its research on lesbian, gay, bisexual and transgender issues, was frequently cited during the same-sex marriage debate for its findings on the positive economic impact of allowing the practice. It also published a widely accepted estimate of the national L.G.B.T. population six years ago.
In the January report, the researchers estimated that 22,200 teenagers in California, 13,800 in Texas and 9,750 in New York would identify as transgender if asked. North Dakota and Wyoming were home to the smallest populations of transgender teenagers, estimated at just 200 each.