However, contemporary medical research and clinical practice often erroneously use sex and gender interchangeably.…
The right question must be asked to obtain the information desired; recent debate around the 2021 census in England has drawn public attention to classification problems.4 The Office of National Statistics, in discussion with stakeholders, recognised that the previous census question that asked, “Are you male or female” without accompanying guidance was insufficient to provide quality information for planning services and monitoring equality. The 2021 England and Wales census5 will collect data on sex (a mandatory question with two answers) and gender identity (a voluntary categorical question plus a free text answer). However, the original accompanying guidance did not clearly explain whether the sex data being sought was legal sex as recorded on a birth or gender recognition certificate, sex as recorded on other administrative documents such as passport or NHS records, or biological sex.
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Ambiguous data collection methods that conflate sex and gender risk erroneous research findings, poor service planning, and lower quality medical practice. Gender and sex should not be used interchangeably. We risk harming patients if we do not understand the difference.