Table 2.

Flaws and limitations of several regret, detransition, and discontinuation studies

Study outcome & rate	Possible limitations	Follow-up time	Loss to follow-up (LTFO)	Defn/how measured	Sample	Intervention/criteria	Ages, notes
Dhejne et al. (2014) Regret 2.2% (4.4% if require 10 yr follow-up, i.e., 1960–2000)	Short min follow-up time, Definition of regret, Sample: older with different criteria for starting	0–50 years	From 1973 to 2003 8.3% dieda, (Full study sample 1960–2010)	Apply for new legal sex/Record search	252 FTM and 429 MTF living adults in Sweden who had applied for and received surgery + legal change	Full surgery/2 year evaluation, sterilization before starting	Median ages for all & for regretters when applied: 27 & 22 (FTM) 32 & 35 (MTF) At least 18 for new legal gender, minimum application 16 years old
*Wiepjes et al. (2018) Regret < 1%	Short min follow-up time, Unclear LTFO, Definition of regret, Search method	Some ≤ 5 years (see Appendix for details of estimate)	36% of everyone at clinic	Reverse hormones and express regret in visit/record search	885 FTM and 1742 MTF who had surgery, treated with hormones at least 1.5 yrs, and who had not dropped out of treatment	Gonadectomy/screening and diagnostic phase	At least 18
Davies et al. (2019) Detransition 0.47%	Unknown follow-up time, Unknown LTFO, Search method, Sample: active clinic patients	Unknown	Unknown	Records in 1 year period/Electronic record scan for words related to detransition or regret plus review by authors	3398 active patients coming to gender clinic in 1 year period	All people in treatment at adult clinic/criteria unknown	Adults (adult clinic)
Hall et al. (2021) Detransition 6.9%, another 3.4% pattern suggesting detransition	Short follow-up time	16 months after discharge	3/175 unclear or transfer	Reverting to original role/retrospective case note review	Natal female: 59 FTM, 8 NB Natal male: 101 MTF, 6 NB, 1 to detransition 175 discharged patients from single national clinic w/in 1 year who did not transfer to another clinic	Mixed/2 assessments	17 and over/1.7% suicides, 2.3% detrans then re-referred Median age at discharge: 20 FTM or NB 36 MTF or NB
*Narayan et al. (2021) Regret 0.2–0.3%	Unknown follow-up time, Unknown LTFO, Regret measure, Sample: encounters	Unknown	Unknown	Express regret in encounter with surgeon/ask surgeons in survey about number of regret encounters	Between 18,125 and 27,325 patients which responding surgeons had operated on (regret encounters did not have to be former patient)	Surgery/criteria mixed	Ages unknown/Rate is regret encounters/Total patients w/surgeries by responding surgeons 62 regretters
Turban et al. (2021) Detransition 13.1% all, 9.1% hormones, 6.8% surgery	Unknown follow-up time, Unknown LTFO, Sample: both required to still be TGNB and non- representativeb	Unknown	Unknown	Self-described detransition/online convenience survey	6289 FTM 7191 MTF 3671 other pursued gender affirmation and still identify as trans or non-binary	Social, hormones, and/or surgery/criteria unknown	11% under 18 when first started living as other gender,  > 18 at time of study
Boyd et al. (2022) Discontinue 20% Detransition 10% Regrets but trans 2.5%	Unclear follow-up time	Unknown	N/A current patients	Discontinue hormones plus eval records/NHS medical records	41 on hormones in GP practice population at regional clinic	Hormones or surgery/Some “affirmed”	Adults who detransitioned took testosterone for a mean of 18 months, presented at median age of 18/“not generalizable”
Roberts et al., 2022 Discontinue  ~ 30%	Short follow-up time	4 years	N/A	Discontinue hormones/Prescription renewals plus still in medical system	627 FTM and 325 MTF who were still eligible for treatment within medical system and still went to it for other medical care	Hormones/criteria unknown	39.1% under 18 when started
Tang et al. (2022) Regret 2/209	Short min follow-up time, Search method, Outcome measure	Some < 1 year	17/209 outcome not documented, 72/209 (34%) do not have at least 1 year follow-up in records	Regret mentioned to surgeon or MHP in system notes/record search	209 patients still in medical system	Double mastectomy/Therapist assessment, surgeon informed consent, real life test for a year preferred	double mastectomy at ages 12–17, all FTM/Regretters at 11 months and 1.5 years
van der Loos et al. (2022) Discontinue 2%	Short min follow-up time	Min, median time since started FTM 0, 2.3 yr MTF 0.1, 3.5 yr	Appears to be 5/720, 3 of whom died	Discontinue prescription/Record search clinic plus insurance	500 FTM 220 MTF	3 month GnRHa and hormones/referred by physician and diagnosed with gender dysphoria	All < 18 when started GnRHa, many became young adults by study end 0.4% died
Jedrzejewski et al. (2023) Regret 0.3%	Short min follow-up time, Unknown LTFO, Regret measure, Sample: encounters	0 (to 1.4) to < 5.6 (to 7) yearsc	Unknown	Request for reversal surgery or encounter of clinic with detransitioner/Encounters at clinic	All 1989 patients operated on from Jan. 1, 2016 to July 31, 2021	Surgery: varied, e.g., chest feminization or masculinization, orchiectomy, hysterectomy	Initial consult mean age 24.5 years old (16–37) Rate: reversal requests or encounter with detransitioner/ total surgeries in same period 6 regretters

*Study quoted in introduction as example of low regret or detransition rate

^aDhejne et al. (2011)

^bD’Angelo et al. (2021)

^cThe regretters had their surgery in the time period January 2016–July 2021. It is not clear when follow-up ended, in principle it could have been any time from July 2021 to December 2022, the month before the paper appeared in January, 2023