We surveyed a sample of young adults who previously identified as transgender but had detransitioned or desisted. Most participants were born female. Mental health issues, including prior diagnoses and a history of self-harm, were especially common. A history of gender dysphoria during childhood was reported by a nontrivial minority of participants. A slight majority believed their histories were consistent with rapid-onset gender dysphoria. Factors most associated with detransition were internal factors, reflecting psychological change, rather than external factors, such as family or social pressure. Detransitioned participants reported that they had become much less gender dysphoric, and much happier, than they were during their period of trans-identification.