Lagos is a sociologist who specializes in how gender is changing in the twenty-first century. Lagos is particularly interested in the social demography of LGBTQ populations. In the paper Lagos will present today, Lagos uses probability sample data from a survey of 39 U.S. states to evaluate popular claims of a “transgender tipping point” by estimating the probabilities of identifying as transgender and gender nonconforming among cohorts of respondents born between 1935 and 2001. The patterns Lagos uncovers provide empirical context for several claims about social change and civil rights related to the transgender tipping point, suggesting that several distinct population-level biographical availability patterns have shaped the prevalence and composition of U.S. transgender and gender nonconforming populations over time.