the.com/breeder

means A person who is heterosexual, especially one who's reproducing the species the old-fashioned way — used as queer slang, often teasing, sometimes pointed.

from The literal sense of 'breeder' — one who breeds, as with livestock or pets — goes back to Middle English 'breden,' meaning to hatch or bring to life. The slang twist came from queer communities, who repurposed the farmyard word to needle heterosexual culture's assumption that pairing off and procreating is the default, natural order. Calling straight couples 'breeders' flips the gaze: suddenly they're the ones being observed, labeled, and mildly amused over, the way humans look at rabbits.