Was curious about whether fellow was actually a gendered term and sharing here for my fellow fellow-curious: www.etymonline.com/word/fellow

fellow | Etymology of fellow by etymonline

"companion, comrade," c. 1200, from Old English feolaga "partner, one who shares with… See origin and meaning of fellow.

Strangely, though, I never seem to hear a woman get called a fellow (singular) unless it’s a title, usually academic. Not sure why that is.