It starts with a burger. In 2008 a Dutch professor named Mark Post presented the proof of concept for what he called “cultured meat.” Five years later, in a London TV studio, Mr. Post and his colleagues ate a burger they had grown from animal cells in a laboratory. Secretly funded by Sergey Brin, a co-founder of Google, the journey from petri dish to plate had cost $325,000 — making theirs the most expensive meal in history. Fortunately, the results were promising: Hanni Rützler, a nutrition scientist, concluded that the patty was “close to meat but not as juicy.” The...