Sex assignment (also known as gender assignment[1][2]) is the discernment of an infant's sex, typically made at birth based on an examination of the baby's external genitalia by a healthcare provider such as a midwife, nurse, or physician.[3] In the vast majority of cases (99.95%), sex is assigned unambiguously at birth. However, in about 1 in 2000 births, the baby's genitalia may not clearly indicate male or female, necessitating additional diagnostic steps, and deferring sex assignment.[4][5]
The prevalence of intersex conditions, where a baby's sex characteristics do not conform strictly to typical definitions of male or female, ranges between 0.018% and 1.7%.[6][7][8] While some intersex conditions result in genital ambiguity (approximately 0.02% to 0.05% of births[4]), others present genitalia that are distinctly male or female, which may delay the recognition of an intersex condition until later in life. [9][10]
Societally and medically, it is generally assumed that a person's gender identity will align with the sex assigned at birth, making them cisgender. However, for a notable minority, assigned sex and gender identity do not coincide, leading to transgender identity experiences. When assigning sex to intersex individuals, some healthcare providers may consider the gender identity that most people with a similar intersex condition develop, although such assignments may be revised as the individual matures.[2][11]
The use of surgical or hormonal interventions to reinforce sex assignments in intersex individuals without informed consent is considered a violation of human rights, according to the Office of the United Nations High Commissioner for Human Rights.[12][2][13][14]
Sex assignment refers to the identification of an infant's sex at birth, typically based on observable physical characteristics. This is also known as gender assignment.[2][15]
In clinical and medical contexts, terms such as "birth-assigned sex" or "birth-assigned gender" are used to describe the sex identified at birth, while "assigned sex" and "assigned gender" may also refer to any subsequent reassignments, especially common among intersex individuals.
The terminology has evolved across various editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM) maintained by the American Psychiatric Association. Initially, the third edition of the DSM referred to "anatomic sex."[16] By the fourth edition in 1994, the term "assigned sex" was introduced, with subsequent editions also using "biological sex" and "natal gender." The latest revision in 2022 streamlined the language to consistently use "sex assignment."[17][2][18]
A 2006 consensus statement on intersex conditions also adopted the terms "assigned sex" and "assigned gender." Sex is assigned as either male or female, leading to specific terms:[11][2][19]
Assigned male at birth (AMAB)
a person of any age and irrespective of current gender whose sex was assigned as male at birth. Synonyms include male assigned at birth (MAAB) and designated male at birth (DMAB).[20][21]
Assigned female at birth (AFAB)
a person of any age and irrespective of current gender whose sex was assigned as female at birth. Synonyms include female assigned at birth (FAAB) and designated female at birth (DFAB).[20][21]
Critics such as Alan Sokal and Richard Dawkins have argued against the "assigned at birth" terminology. In a 2024 op-ed for the Boston Globe, they contended that sex is an "objective biological reality" determined at conception and observed at birth, rather than assigned. They say that using "assigned" terminology, which they view as an example of "social constructionism gone amok," distorts scientific facts and could undermine trust in medical institutions.[23]
Assignment in cases of infants with intersex traits, or cases of trauma
Observation or recognition of an infant's sex may be complicated in the case of intersex infants and children and in cases of early trauma. In such cases, the infant may be assigned male or female, and may receive intersex surgery to confirm that assignment. These medical interventions have increasingly been seen as a human rights violation due to their unnecessary nature and the potential for lifelong complications.[24][25][13]
The Phall-O-Meter satirizes clinical assessments of appropriate clitoris and penis length at birth, and the definition of ambiguous genitalia. It is based on research published by Suzanne Kessler.
Cases of trauma include the famous John/Joan case, where sexologist John Money claimed successful reassignment from male to female of a 17-month-old boy whose penis was destroyed during circumcision. However, this claim was later shown to be largely false. The subject, David Reimer, later identified as a man.[26]
The number of births with ambiguous genitals is in the range of 1 in 2,000 to 1 in 4,500 (0.05% to 0.02%).[4] Typical examples would be an unusually prominent clitoris in an otherwise apparently typical girl, or complete cryptorchidism in an otherwise apparently typical boy. In most of these cases, a sex is tentatively assigned and the parents told that tests will be performed to confirm the apparent sex. Typical tests in this situation might include a pelvic ultrasound to determine the presence of a uterus, a testosteroneor17α-hydroxyprogesterone level, and/or a karyotype. In some of these cases a pediatric endocrinologist is consulted to confirm the tentative sex assignment. The expected assignment is usually confirmed within hours to a few days in these cases.
Some infants are born with enough ambiguity that assignment becomes a more drawn-out process of multiple tests and intensive education of the parents about sexual differentiation. In some of these cases, it is clear that the child will face physical difficulties or social stigma as they grow up, and deciding upon the sex of assignment involves weighing the advantages and disadvantages of either assignment. Intersex activists have criticised "normalising" procedures performed on infants and children, who are unable to provide informed consent.[25]
The words "sex assignment" came into use in the late 1950s and early 1960s.[27]
In European societies, Roman law, post-classical canon law, and later common law, referred to a person's sex as male, female, or hermaphrodite, with legal rights as male or female depending on the characteristics that appeared most dominant. Under Roman law, a hermaphrodite had to be classed as either male or female.[28] The 12th-century Decretum Gratiani states that "Whether a hermaphrodite may witness a testament, depends on which sex prevails".[29][30] The foundation of common law, the 16th Century Institutes of the Lawes of England, described how a hermaphrodite could inherit "either as male or female, according to that kind of sexe which doth prevaile."[31][32] Legal cases where sex assignment was placed in doubt have been described over the centuries.
With the medicalization of intersex, criteria for assignment have evolved over the decades, as clinical understanding of biological factors and diagnostic tests have improved, as surgical techniques have changed and potential complications have become clearer, and in response to the outcomes and opinions of adults who have grown up with various intersex conditions.
Before the 1950s, assignment was based almost entirely on the appearance of the external genitalia. Although physicians recognized that there were conditions in which the apparent secondary sexual characteristics could develop contrary to the person's sex, and conditions in which the gonadal sex did not match that of the external genitalia, their ability to understand and diagnose such conditions in infancy was too poor to attempt to predict future development in most cases.
Sex assignment became more than choosing a sex of rearing, but also began to include surgical treatment. Undescended testes could be retrieved. A greatly enlarged clitoris could be amputated to the usual size, but attempts to create a penis were unsuccessful. John Money and others controversially believed that children were more likely to develop a gender identity that matched sex of rearing than might be determined by chromosomes, gonads, or hormones. The resulting medical model was termed the "Optimal gender model".[33]
In recent years, the perceived need to legally assign sex is increasingly being challenged by transgender, transsexual, and intersex people.[34][35] A report for the Dutch Ministry of Security and Justice states "Gender increasingly seems to be perceived as a 'sensitive' identity feature, but so far is not regarded, nor protected as such in privacy regulations".[34] Australian government guidelines state that "departments and agencies that collect sex and/or gender information must not collect information unless it is necessary for, or directly related to, one or more of the agency's functions or activities"[36]
Sex registration was introduced in the Netherlands in 1811 due to gender-specific rights and responsibilities, such as military conscription.[34] Many gender-specific provisions in legislation no longer exist, but the provisions remain for rationales that include "speed of identification procedures".[34]
^Raming, Ida; Macy, Gary; Bernard J, Cook (2004). A History of Women and Ordination. Scarecrow Press. p. 113.
^E Coke, The First Part of the Institutes of the Laws of England, Institutes 8.a. (1st Am. Ed. 1812) (16th European ed. 1812).
^Greenberg, Julie (1999). "Defining Male and Female: Intersexuality and the Collision Between Law and Biology". Arizona Law Review. 41: 277–278. SSRN896307.
