This book provides the first compilation of demographic research focused on transgender, nonbinary, and gender minority populations. It discusses the measurement and conceptualization challenges that shape demographic knowledge of these populations, including how we capture gender on surveys. It examines our current knowledge of demographic characteristics and health disparities and outcomes. Overall, this research demonstrates the increasing knowledge of gender variation at the population level. At the same time, it reveals the need for better survey questions, additional data, and inquiry...