How the word “gender” got separated from biological sex

A polite way to avoid saying “sex”
In many languages the blunt word “sex” carries a bedroom meaning or sounds too animal-like, so people reached for the softer word “gender.” One detrans man remembers that in his mother-tongue “‘gender’ is the polite form of saying sex, as ‘sex’ carries a dirty undertone.” – Liquid_Fire__ source [citation:57102fef-41fa-46c9-9770-19ccdeb5fe6e]
Because everyday speech already used the two words interchangeably, later writers had an opening to give “gender” a brand-new definition.

Doctors who needed a reason to operate on intersex babies
The first deliberate split between sex and gender was made by mid-20th-century physicians. They wanted to assign intersex newborns to one of the two socially accepted categories, usually girls, and argued that “the sex of a person has no bearing on their gender.” – sprachgenie source [citation:11313149-b87d-42f4-8f5c-c7a0c227cafe]
Calling the child’s future social role “gender” let surgeons claim they were only adjusting the body to match the child’s supposed inner identity, not changing an immutable biological fact.

A single word that kept the meanings fused
Some languages never developed two separate terms. A Norwegian detrans woman points out that “in my first language ‘gender’ and ‘sex’ doesn’t get distinguished and it’s only one word for it: ‘kjønn’.” – snorken123 source [citation:ffa51b78-1d6e-4608-8171-19068ae6cde0]
Where one word covers both ideas, the modern claim that they are totally different concepts feels like a recent ideological invention rather than common sense.

Activists who widened the gap
Once “gender” was floating around as a polite, vague term, trans advocates could quietly redefine it as an inner feeling. A detrans man noticed that even as a child he used the word this way: “I used to say ‘People can act and dress the way they want to no matter their gender’… I was also using the word gender as a euphemism for sex.” – KardomonEverest0 source [citation:d704b463-c1f4-4097-bf5d-4b732ea93541]
Over time the euphemism hardened into the belief that gender is a private identity completely separate from the body.

Bottom line
“Gender” started as a courteous stand-in for biological sex. Mid-century doctors used that politeness to justify surgery on intersex infants, and later activists used the same vagueness to argue that gender is an inner essence detached from biology. Recognizing this history helps anyone questioning their identity see that the split between sex and gender is not ancient truth but a social shift—one that can be questioned without medical steps, through simple, honest self-acceptance and freedom from stereotyped roles.