About 21% of Generation Z Americans who have reached adulthood — those ages 18 to 25 — identify as lesbian, gay, bisexual, transgender or something other than heterosexual, according to a recent Gallup poll.

This is about double the number compared to millennials at about 10.5%, and the gap increases compared to older generations, according to Gallup. About 4.2% of Generation X (born 1965 to 1980) and about 2.6% of Baby Boomers (born 1946 to 1964) identify as LGBT, according to Gallup. Only 0.8% of those born before 1946— Traditionalists — identify as LGBT, the Gallup poll says.