How many trans people are there in the U.S., and why do we overestimate it?

State legislators introduced hundreds of 2023 bills targeting transgender Americans and affecting access to health care, education policy and sports. To hear the political discourse, it sounds at times as if the United States’ transgender population is large, booming and influential.

"Trans ideology is coming after our children," tweeted U.S. Rep. Marjorie Taylor Greene, R-Ga., on July 11.

Republican presidential candidate Vivek Ramaswamy misleadingly described being transgender as a "social contagion" and a mental illness that is spreading "like wildfire across this country."

The Twitter account Gays Against Groomers alerted its 343,000 followers July 5 to a notable figure: "New...