Statistically speaking, How common is it for the doctor/midwife, whoever genders the baby, to misassign the person's biological sex at birth?

What's the closest number to zero that you can think of? It's that

Is more than zero because there are a percentage of people with DSD? 

16 minutes ago, Javaxcore said:

Is more than zero because there are a percentage of people with DSD? 

But you specified biological sex, so essentially zero is the right answer.

It would seem to be that however small the risk might be it is not insignificant since the BBC recently highlighted cases of misdiagnosis and I find on looking for them that there is an american standard on the subject.

https://pubmed.ncbi.nlm.nih.gov/25944182/

There are a number of genetic causes of intersex individuals, some of which render the physical attributes of the individual to be discordant with their underlying genetics (e.g. AIS resulting in XY individuals with undescended testes and a vagina, or CAH resulting in XX individuals with masculine traits). I imagine that these conditions - typically with frequencies of one in thens of thousands might contribute to discrepancies in the designation of biological sex at birth.  

9 minutes ago, Arete said:

There are a number of genetic causes of intersex individuals, some of which render the physical attributes of the individual to be discordant with their underlying genetics (e.g. AIS resulting in XY individuals with undescended testes and a vagina, or CAH resulting in XX individuals with masculine traits). I imagine that these conditions - typically with frequencies of one in thens of thousands might contribute to discrepancies in the designation of biological sex at birth.  

Thank you for that knowledgable amplification.

Karyotype, Genital development, psychological gender.

Extra chromosomes usually abort, but trisomy 21 and 18 are not always lethal to the fetus, and extra sex chromosomes in Klinefelter's et cetera are virtually harmless.  Klinefelter's people still have male genitalia, but the condition results form extra X's and not extra Y's, making it the closest thing to an ambiguous gender karyotype.

In rare cases genital development is ambiguous, but I am unaware of the relationship between intersex genitalia and extra sex chromosomes.  I would imagine that some countries include an "intersex" option for newborns.

Psychological gender depends on the brain and maybe even socialization.  Anthropologists know that historically many cultures recognized people of a "third gender."  Autistic people are on average less gender conforming.  Dissociative identity disorder (DID) involves "identity disturbances" that can include amnesia, leaving home (as in dissociative fugue), altered dialect (an accent), and yes gender changes.

In many cases, there are intersex scenarios, third gender or transgender scenarios, or in rare cases a destabilization of gender (as a psychological trauma coping mechanism).  Moreover, I think our culture and probably most cultures have a tendency to genderize emotional stsates and their expression even though the notion of a gender-specific emotion is absurd.

Paul Ekman's research identified 6 or 7 universal emotions until the Fore of Papua Guinea whittled it down to 5.  Happy, sad, angry, fearful/surprised, and contempt was dropped.

... 6: forgot disgust.