Sex assignment at birth

Sex assignment at birth (sometimes called gender assignment as there is no clear division between the recorded gender and sex of an infant) refers to the sex that an observer declares the baby to be shortly after birth. Although uncontroversial in the past, the "recognition" of trans people, intersex people, and non-binary gender renders this procedure problematic. People question whether we should place so much emphasis on a child's sex, in view of the many people who later question their assigned sex. Some advocates for trans, non-binary, and intersex people also think it should be possible to omit gender assignment or allow non-binary gender options. Or potentially the procedure for recording births could be altered so a child's apparent sex is recorded medically (along with birth weight, etc) but does not carry any importance beyond that.

A breakdown of the terms and abbreviations involved:
 * People with vulvas are declared to be "girls", and are thus "assigned female at birth" (AFAB) or "female assigned at birth" (FAAB).
 * People with penises are declared to be "boys" and thus "assigned male at birth" (AMAB) or "male assigned at birth" (MAAB).
 * Another way of stating this is to write DFAB or DMAB, the d standing for "designated".
 * Some people, especially trans people, use the term "CAFAB" or "CAMAB", the C standing for "coercively". Another term, "FAFAB" or "FAMAB", exposes the mandatory assignation of sex at birth (the F standing for "forcibly").

Criticism of conventional procedures for gender assignment parallels debates about whether adults should be able to record their gender as non-binary, for instance with an 'X' on a passport: many changes would be necessary for people to exist without a binary gender assignment both in childhood and adulthood, but these changes would make life easier for people who are uncertain or disagree with their gender assignment or do not wish to be assigned either gender.

Conventional procedure
The doctor (or midwife, or whoever else is present) examines the infant and declares "It's a boy!" if a penis is present or "It's a girl!" if a vulva is present. Determination can also be done before birth using an ultrasound, allowing people to paint their nurseries blue or pink. But the importance of sex assignment at birth is that this value is recorded on official documentation, such as the birth certificate, and the child is therefore classified as a specific sex, and this value may then be used by the state for numerous purposes. In most societies it is difficult, bureaucratic, and occasionally impossible to change legally-specified gender once assigned at birth, so this determination carries costs.

Intersex people and surgery
In the case of certain intersex conditions, the obstetrician or midwife may not be able to unambiguously classify a child as male or female, as the genitalia of the infant may be ambivalent. In the US around 1 in 2000 babies are intersex, where there is some uncertainty based on the development of sexual characteristics. Sometimes an attempt is made to assign gender more or less arbitrarily even if it is ambiguous, although there is no guarantee that this will match the gender identity that the child later expresses. In some cases, intersex infants can be forced to undergo surgery to establish them as externally one sex or another. However, more recently, there is a trend not to perform "gender-normalising" surgery in infancy, and to defer sex assignment until the child is old enough to make the decision.

There are also rare cases such as who was assigned male at birth based on observation of male genitalia, but following a botched circumcision aged 7 months he was given vaginoplasty, reassigned as a female and raised as a girl, before much later experiencing gender dysphoria and choosing to be a man.

Terminology
The terms "AMAB" or "AFAB" are generally preferred over the terms "female-bodied/male bodied" or "anatomically male/anatomically female", or "biologically male/biologically female", as these terms automatically assign a gender to certain body parts, and do not take into account the possibility that the individual in question may have undergone surgery to change their genitals. "Genetic/biological male" or "genetic/biological female" are also incorrect terms, as certain intersex conditions can cause one to have XY chromosomes but be born with a vulva, or have XX chromosomes and be born with a penis.