Intended for healthcare professionals

Rapid response to:


Rethinking sex-assigned-at-birth questions

BMJ 2021; 373 doi: (Published 24 May 2021) Cite this as: BMJ 2021;373:n1261

Rapid Response:

Biological sex is vital in healthcare

Dear Editor

This editorial appears to argue against the use of clear language to describe biological sex in medicine. The authors seem to take a rather myopic view of this issue, framing it as one rooted in transgender rights and who holds power in “assigning sex,” instead of basic principles.

Human beings, of course, reproduced sexually long before modern medicine, birth certificates, or the word “transgender” first came to be. The truth of the sex binary is anchored in the mechanism that brings every human into existence.[1] Humans have two different types of gametes, two types of reproductive systems, two discrete reproductive roles: two sexes. As a result, we have given these two sexes different names: female and male. These will exist whether or not the clinician writes them down, or asks a transgender patient “what is your sex?” The fact that 0.02% of babies[2] have differences in sex development that cause the usually easy identification of sex to become a more complex affair, does not invalidate sex as one of the most clinically useful categorisations in medicine. To suggest that it does, and therefore sex should not be recorded, is absurd. If the accuracy of observable sex is claimed not to be good enough for doctors to record or rely on in medical practice, this would logically put doctors in a position where any data they have would need to reach an accuracy threshold far exceeding most tests. Even by the authors’ own statistic of 98%, it sets an impossibly high bar.

The authors write:
“However, no evidence exists that clinicians with knowledge of assigned sex provide better care, and recent qualitative research suggests that most transgender people do not believe people should be asked about their sex assigned at birth.”

It seems unlikely that a study to determine whether or not clinicians should have adequate knowledge of a patient’s natal reproductive biology would pass ethics approval. Such a study would risk patient safety. Analyses of the purpose of recording sex[3,4], knowledge of the numerous genetic, anatomical and physiological differences between females and males[5], and accounts from transgender patients where healthcare has been poorer because natal sex was not recognised[6] suggest clinicians’ knowledge of reproductive biology is, in fact, vital to healthcare. It is unclear why the authors posit that transgender people require the medical profession to abandon scientific terms describing specific biology, and to do so for the entire population. Other commentators might view this situation as highlighting a real need to better explain the salience of biological sex to all people.[7]

The authors also write:
“Changes to bodies over a lifetime—for example, through hysterectomy or orchiectomy—may also render sex assignment an incomplete or obsolete assessment of anatomy and physiology. Questions about sex assigned at birth cannot serve as shorthand for anatomy (Do I need to add testicular torsion to my differential diagnosis?), hormones (Do I need to consider the role of oestrogen in this person’s thromboembolism?), or screening needs (Would cervical smear testing improve this person’s health outcomes?).”

No rational argument appears to be made as to why doctors should avoid admitting that the patients who had hysterectomies are biologically female, and those who had orchiectomies male. Surgery on reproductive organs does not render sex obsolete. A lobectomy does not make the respiratory system redundant. While the authors dismiss information gained from knowledge of biological sex as “shorthand,” knowledge of the two types of reproductive systems, and being able to name them, is important. This holds true for gender clinicians, too. The patient referral form for the Gender Identity Clinic in London asks for “sex assigned at birth.”[8] It seems strange to suggest medicine should have no names for the distinctions between the people at risk of testicular torsion versus cervical cancer. Communication skills usually advise against reducing people to their organs, to avoid saying “the pancreas in room 7,” but even if some form of organ-inventory system were proposed, it seems likely the basic template would come in two distinct types.

Gender identity information can be valuable to help guide the clinical encounter, respect the transgender patient’s sense of self and gain a fuller picture as to healthcare needs. But gender identity should be recorded in addition to, not act as a replacement for, biological sex. If an unknown patient comes in to A&E, unaccompanied and unconscious, their gender identity would not be ascertainable. However, their sex would remain observable, and would make a difference to that patient’s care.

Healthcare cannot collectively discard words for the two biological sexes. Awareness of the importance of clinical research into sex differences in medicine, especially for the female sex[9], has just been highlighted by the pandemic. How would such work be done if the sexes cannot be named?

Clear language on sex is vital in medicine, science, and public health education.

It is surprising these words should need to be typed in a Rapid Response to the BMJ.[10]

1 Marinov GK. In Humans, Sex is Binary and Immutable. Acad Quest 2020;33:279–88. doi:10.1007/s12129-020-09877-8
2 Sax L. How common is lntersex? A response to Anne Fausto‐Sterling. J Sex Res 2002;39:174–8. doi:10.1080/00224490209552139
3 Dahlen S. De-sexing the Medical Record? An Examination of Sex Versus Gender Identity in the General Medical Council’s Trans Healthcare Ethical Advice. New Bioeth 2020;26:38–52. doi:10.1080/20502877.2020.1720429
4 Wheater E. Recording sex on medical records: a case study of NHS Scotland. Murray Blackburn Mackenzie Policy Anal. 2020.
5 Mauvais-Jarvis F, Bairey Merz N, Barnes PJ, et al. Sex and gender: modifiers of health, disease, and medicine. Lancet 2020;396:565–82. doi:10.1016/S0140-6736(20)31561-0
6 Gorvett Z. Why transgender people are ignored by modern medicine. BBC Futur. 2020.
7 Wright C, Hilton E. The Dangerous Denial of Sex. Wall Str. J. 2020.
8 Gender Identity Clinic. Referrals.
9 Dahlen S. Dual Uncertainties: On Equipoise, Sex Differences and Chirality in Clinical Research. New Bioeth 2021;:1–11. doi:10.1080/20502877.2021.1917100
10 Bewley S, McCartney M, Meads C, et al. Sex, gender, and medical data. BMJ 2021;:n735. doi:10.1136/bmj.n735

Competing interests: No competing interests

26 May 2021
Sara Dahlen
MSc Student, Bioethics and Society
King's College London