Let me offer an argument that I view as a variation on the position expressed above by the PETA member who viewed PETA's prize as controversial. The goal of the animal rights community (as opposed, for example, to the animal welfare community) is to eliminate the use of animals as resources to be mined (for their milk, eggs, wool, etc.) and killed (for their flesh), all of which use involves tremendous suffering. One way to express opposition to the use of animals is to become a vegan and thus to reduce the aggregate demand for animal use by refusing to subsidize it. By irritating grocers and waiters at restaurants -- not to mention fellow diners -- the vegan serves also as a gadfly, thereby spreading the message that eating meat directly contributes to unfathomable and unjustifiable suffering. If a vegan were to begin to consume in vitro meat (which might be physiologically indistinguishable from "in vivo" meat), then her food choices might become immediately less apparent to those around her. She could order a cheeseburger at a restaurant that stocks in vitro meat, without guilt but also without signaling to her dinner companions that she believes that eating meat represents a morally reprehensible act. Furthermore, she herself might come to view meat as acceptable, having eaten its physiologically identical analogue, so that when a restaurant does not stock in vitro meat, she might feel disinhibited from ordering it.
This latter concern is one that comes up for people I know who say that they eat only organically raised animals and organic milk and cheese. They believe, inaccurately as it turns out, that organic farming gives animals a good life until the moment that they are slaughtered. I regularly see such people order meat dishes in restaurants that do not insist on organic meat, however. In other words, once you allow yourself to eat organic meat, you are likely to eat factory-farmed meat when the organic alternative is not available. Compromise yields more compromise.
I wonder, however, whether a vegan eater of in vitro meat might feel that she has not compromised at all. If no animal lived or suffered or died to produce the burger, then how different is that burger from a flame-grilled soy patty? And if one takes this view, then the line between eating meat that came from a real animal and meat that came from a non-sentient stem cell might remain firm in one's mind. In other words, one must accept the premise that in vitro meat represents a compromise to conclude that such a compromise risks further compromise.
Posted by Sherry F. Colb