Where did the chop-chop trope come from?

cross-posted from: https://lemmygrad.ml/post/3169170

One major transphobic argument I see - especially towards trans men - is trans ppl chopping off their genitals and tits to transition (which isn't true).

The misconception stems from sex reassignment surgery. The question I have is how does SRS actually work and what percent of trans ppl actually undergo SRS?