A lab-grown hamburger — made from beef raised in a petri dish instead of a pasture — cost scientists more than $300,000 to produce, and it doesn't taste half-bad, say the people who have tried it.

Beef is growing in the Petri dishes of ETH professor Ori Bar-Nur, an expert in regenerative and muscle biology. However, he hasn't yet tasted the cultivated meat because human consumption requires ...