Down the hall, in a lab with incubators filled with clear plastic containers holding a pinkish liquid, a technician was tending to the delicate task of growing the tens of billions of cells needed to make the burger, starting with a particular type of cell removed from cow necks obtained at a slaughterhouse.

The idea of creating meat in a laboratory — actual animal tissue, not a substitute made from soybeans or other protein sources — has been around for decades. The arguments in favor of it are many, covering both animal welfare and environmental issues.

A 2011 study in the journal Environmental Science and Technology, for example, showed that full-scale production of cultured meat could greatly reduce water, land and energy use, and emissions of methane and other greenhouse gases, compared with conventional raising and slaughtering of cattle or other livestock. Those environmental arguments will only gain strength, advocates say, as worldwide demand for meat increases with the rise of middle-class populations in China and elsewhere.

Dr. Post, one of a handful of researchers in the field, has made strides in developing cultured meat through the use of stem cells — precursor cells that can turn into others that are specific to muscle, for example — and techniques adapted from medical research for growing tissues and organs, a field known as tissue engineering. (Indeed, Dr. Post, a physician, considers himself first and foremost a tissue engineer, and about four-fifths of his time is dedicated to studying how to build blood vessels.)