Low regret figures such as 0.3–0.6% are often quoted to show that detransition is rare. In this opinion piece, J. Cohn argues that the true rates are unknown. He sets four conditions for a sound study: long enough follow-up (published times to regret range from about 3 to over 10 years), few people lost along the way, clear definitions and suitable measures, and patients like today's, who are mostly teenage girls. None of the studies in a 2021 review of surgery regret followed at least 85% of people for 8 or more years. Studies reporting higher rates fail the same tests. It is a useful checklist for reading regret studies, but it offers argument, not new data. Some of its cut-offs are judgement calls, and the author works with SEGM (the Society for Evidence-Based Gender Medicine), which urges caution in youth gender medicine.
The detransition rate is unknown. Existing studies claiming low regret or detransition rates (0.3-0.6%) are unreliable due to methodological flaws including: insufficient follow-up time (often shorter than observed median times to regret of 7.5-8 years), high loss to follow-up, inappropriate measurement instruments, and non-representative samples that differ from current patient populations. The frequently quoted extremely low rates are based on studies with adults who underwent extensive screening under older protocols, not the current adolescent-onset cohort with different characteristics. Until properly designed long-term studies are conducted with adequate follow-up duration, small loss to follow-up, appropriate definitions and measurement tools, and relevant samples, the true rates of discontinuation, detransition, and regret cannot be determined. This uncertainty should be communicated to patients and families as part of informed consent for gender-affirming medical interventions.