We may need to take "feeding our young" out of the category of things humans do better than animals. In China, cows are being engineered to produce milk intended to replace human breast milk.
Chinese scientists introduced human genes into bovine embryos in 2011, creating dairy cows whose milk "is identical to the human variety and has the same immune-boosting and antibacterial qualities as breast milk."
The product is still undergoing tests, but animal welfare advocates are not on board. During two experiments led by the Chinese researchers, 10 of the 42 calves died shortly after birth. Six more died within six months. A spokesman for the Royal Society for the Protection of Animals in the U.K. said the organization was "extremely concerned" about how these cows were being produced. Helen Wallace, director of GeneWatch UK, a biotechnology monitoring firm, echoed those sentiments, saying, "Ethically there are issues about mass producing animals in this way."
The Chinese researchers tout the milk's enhanced protein content, which includes lysozyme, an antimicrobial protein that protects newborns from bacterial infections. It's naturally found in high amounts in human breast milk but low amounts in cow's milk.
Determining whether the milk is safe is another story. "It is really hard to tell that, unless you do large clinical trials like you would a drug," Wallace said. "So there will be uncertainty about whether it could be harmful to some people."