History: Denim jeans for workers, not 'men' or 'women'

Jeans by Mabel Amber, who will one day from Pixabay

Denim jeans are for workers:

"Women had begun wearing pants — specifically, denim jeans — because they were granted practical permission in industrial factory work during World War II. Women had not earned 'the right to wear pants' as a symbolic legal right, or as a matter of formal equality. The police had simply chosen, for obvious reasons, not to arrest them for wearing pants to and from work. Their pants were tied to their work, to the class status of being a worker in the formal labor market and the public sphere."

— "The Left Hand of the Law": Anti-Drag Law's Policing Ought to Inform Political Responses, Jules Gill-Peterson, Sad Brown Girl (Substack), Feb 27, 2023

Later, jeans are not explicitly men's clothing, but not necessarily women's clothing either:

“Those who do not want to change their anatomy but do want to change their gender behavior fare less well in establishing their social identity. The women Holly Devor called ‘gender blenders’ wore their hair short, dressed in unisex pants, shirts, and comfortable shoes, and did not wear jewelry or makeup. They described their everyday dress as women’s clothing: One said, ‘I wore jeans all the time, but I didn’t wear men’s clothes’ (Devor 1989, 100). Their gender identity as women, but because they refused to ‘do femininity,’ they were constantly taken for men (1987, 1989, 107-42). Devor said of them: ‘The most common area of complaint was with public washrooms. They repeatedly spoke of the humiliation of being challenged or ejected from women’s washrooms. Similarly, they found public change rooms to be dangerous territory and the buying of undergarments to be a difficult feat to accomplish’ (1987, 29). In an ultimate ironic twist, some f these women said ‘they would feel like transvestites if they were to wear dresses, and two women said that they had been called transvestites when they had done so’ (1987, 31). They resolved the ambiguity of their gender status by identifying as women in private and passing as men in public to avoid harassment on the street, to get men’s jobs, and, if they were lesbians, to make it easier to display affection publicly with their lovers (Devor 1989, 107–42). Sometimes they even used men’s bathrooms. When they had gender-neutral names, like Leslie, they could avoid the bureaucratic hassles that arose when they had to present their passports or other proof of identity, but because most had names associated with women, their appearance and their cards of identity were not conventionally congruent, and their gender status was in constant jeopardy. When they could, they found it easier to pass as men than to try to change the stereotyped notions of what women should look like.”
Judith Lorber. Paradoxes of Gender. Yale University, 1994. Chapter: “‘Night to His Day’: The Social Construction of Gender” (PDF). p. 21.