NASA decided to give it a try, because they thought their astronauts would be able to eat meat in space that way. They began a research program, but the scientists just got a layer of pig tissue -- astronauts would just have to be vegetarian.
To build meat on Earth, they separate stem cells from muscle cells. They then put it in a nutrient-rich jelly. It might not work, however. Making a small pork chop would require letting the cells sit for 30 days. However, we may be able to develop advanced technology such as "Cell Incubators" to breed fake meat.
Is it really humane to do this? Although it allows some pigs to be saved, it still makes for an unlucky few to be killed for their cells. Vegetarianism is definitely a better policy, as it doesn't allow any pigs to be killed (for cells or meat).
This is still important, however, as a million pork cells = 999,999 pigs saved from the slaughterhouse......