There are many similarities between humans and pigs that make the idea of interspecies organ transplants seem viable. However, human bodies reject pig organs because of specific DNA sequences our bodies can’t process. Science has long toiled over a solution to this problem, thinking that it might be solved by genetic modification. And now, the first genetically engineered pigs have been born in China. The 15 pigs will grow no larger than 150 pounds (68 kg), and have organs of perfect size to transplant into humans.