The scientist behind this historic event is Dr Mark Post, of the University of Maastricht, in the Netherlands. The idea is simple: take some muscle tissue from a single cow and grow it in a nutrient solution. It will multiply and eventually we will have something that really is meat, cell for cell. In practice, however, there are many obstacles to overcome. We aren't even close to growing chicken breasts, or a steak. The first objective is to produce a hamburger, and this week's tasting is intended to demonstrate that it can be done. The hamburger will consist of real bovine muscle tissue, but it was never part of a cow that suffered, or belched methane as it digested its food.
Should beef producers look for some other line of work? Eventually, perhaps, but not quite yet; the cost of producing the piece of hamburger that will be tasted exceeds PS200,000.
Still, once the researchers have found ways of overcoming the initial obstacles, there is no reason in vitro meat should not be competitive in price with meat from animals. Most of the meat sold today comes from animals that have been fed on grain or soya beans. Those crops had to be grown and transported to the animals, who then use part of the nutrients from their food to produce bone or other body parts that we do not eat. It ought to be possible to make considerable savings by going directly from the nutrients to the meat.
There are important ethical reasons why we should replace animal meat with in vitro meat, if we can do it at reasonable cost. The first is to reduce animal suffering. Just as the cruelty inflicted on working horses, so movingly depicted in Anna Sewell's Black Beauty, was eventually eliminated by the efficiency of the internal combustion engine, so the vastly greater quantity of suffering that is inflicted on tens of billions of animals in today's factory farms could be eliminated by a more efficient way of producing meat.
You would have to have a heart of stone not to applaud such an outcome. But it needn't be simply an emotional response. Among philosophers who discuss the ethics of our treatment of animals there is a remarkable degree of consensus that factory farming violates basic ethical principles that extend beyond the boundary of our own species. Even a staunch conservative such as Roger Scruton, who vigorously defended hunting foxes with hounds, has written that a true morality of animal welfare ought to begin from the premise that factory farming is wrong.
The second reason for replacing animal meat is environmental. Using meat from animals, especially ruminants, is heating the planet and contributing to a future in which hundreds of millions of people become climate refugees. Much of the emissions from livestock is methane, an extremely potent greenhouse gas emitted by ruminant animals as they digest their food. In vitro meat won't belch or fart methane. Nor will it defecate, and as a result, the vast cesspools that intensive farms require to handle manure will become unnecessary. With that single change, the world's production of nitrous oxide, another powerful contributor to climate change, will be slashed by two-thirds.
The United Nations Food and Agriculture Organisation has acknowledged that greenhouse gas emissions from livestock exceed those from all forms of transport - cars, trucks, planes and ships - combined. On some calculations, livestock emissions in countries with large populations of cattle and sheep can make up as much as half of the country's total greenhouse gas emissions. If they are right, replacing coal and other fossil fuels with clean sources of energy is not going to be enough. We have to reduce the number of cattle on the planet.
Some vegetarians and vegans may object to in vitro meat, because they don't see the need for meat at all. That's fine for them, and of course they are free to remain vegetarians and vegans, and choose not to eat in vitro meat. My own view is that being a vegetarian or vegan is not an end in itself, but a means towards reducing both human and animal suffering, and leaving a habitable planet to future generations. I haven't eaten meat for 40 years, but if in vitro meat becomes commercially available, I will be pleased to try it.