Half of Americans in Gallup’s 2018 Values and Beliefs poll say that being gay or lesbian is a trait from birth, easily eclipsing the 30% who believe it is a product of upbringing and environment. This is consistent with findings over the past few years. Another 10% say both explanations play a role, while 4% attribute being gay to something else and 6% are unsure.

When Gallup first asked this “nature vs. nurture” question in 1977, a majority of U.S. adults (56%) said being gay or lesbian was due to people’s upbringing and environment, and only 13% saw it as a birth trait. Attitudes didn’t shift markedly until after 1989. Between 1989 and Gallup’s next update in 1996, the percentage believing sexual orientation is determined at birth jumped from 19% to 31%, and reached 40% by 2001. Opinion remained steady for the next 12 years, as Americans were roughly split between the two positions. Since 2012, the percentage assigning sexual orientation to nature rather than nurture has inched up another 10 percentage points.