Scientists have been breeding genetically modified animals for decades, and assert they are perfectly safe, but to date none has been admitted into the U.S. food supply, reported Jef Akst on The Scientist.

The article reviewed the case of Enviropig, which was modified to produce lower levels of phosphorus in its manure, an environmental benefit because phosphorus can leach into groundwater beneath pig farms. The transgene also eliminates the cost of adding phosphorus to the animals' feed. Anti-GMO activists voiced loud opposition.

"They really targeted it and made it a bad thing," said