Lab-grown meat once depended on calf blood

Cultured meat is pitched as a cruelty-free utopia, but the cells refuse to grow unless they are bathed in a highly specific nutrient broth. For years, this meant relying on fetal bovine serum, a liquid extracted directly from calf blood, just to coax the cells into multiplying. We effectively grew synthetic meat by relying on the very animals we were trying not to eat.