These pig cells were able to co-exist safely with the human cells for the 25 weeks of the study.

BBC: NEWS | Health | Pig organs may be safe for humans

"I do think it's probably better to live in a place where they are able to root, graze and be a pig, " says Pernice, who lives in a detached house with a large yard.

WSJ: Pigs May Fly Before Finding a Legal Home in the City

"I do think it's probably better to live in a place where they are able to root, graze and be a pig, " says Pernice, 50, who lives in a detached house with a large yard.

WSJ: New Yorkers boldly flout law to keep pigs

That is mostly produced by the nitrogen in pig manure, and the team of scientists said they might one day be able to tackle that problem too.

BBC: GM pigs to produce cleaner manure