The facility lies midway between Munich’s city center and its international airport, roughly 23 miles to the north. From the outside, it still looks like the state-run farm it once was, but peer through the windows of the old farmhouse and you’ll see rooms stuffed with cutting-edge laboratory equipment.

In a newer building at the back of the farm, Barbara Kessler pulls off her sneakers and sprays her bare feet and hands with antiseptic. The wiry veterinarian steps over a taped line in the shower room, leaving behind everything she can from the outside world: clothes, watch, earrings. She scrubs her body and hair—a buzz cut, so it’s easier to manage these frequent washings.

After the shower, she finds her size among the neat stacks of supplied clothes and pulls on a pair of black pants, a red shirt, and black Crocs. Outside the dressing room, she adds a black knit cap to keep even her short-cropped hair from passing on germs, and then strides down the hall to the boot room, where she carefully steps into knee-high rubber boots that are power-washed after each wearing.

LAETITIA VANCON

All these precautions are to protect animals not known for their cleanliness: pigs. And once Kessler opens the door to the indoor pens, the smell is unmistakable. It’s a pigsty, after all.

When Kessler unlocks one pen to show off its resident, a young sow wanders out and starts exploring. Like other pigs here, the sow is left nameless, so her caregivers won’t get too attached. She has to be coaxed back behind a metal gate. To the untrained eye, she acts and looks like pretty much any other pig, but smaller.

It’s what’s inside this animal that matters. Her body has been made a little less pig-like, with four genetic modifications that make her organs more likely to be accepted when transplanted into a human. If all goes according to plan, the heart busily pumping inside a pig like this might one day beat instead inside a person.

Different types of tissues from genetically engineered pigs are already being tested in humans. In China, researchers have transplanted insulin-producing pancreatic islet cells from gene-edited pigs into people with diabetes. A team in South Korea says it’s ready to try transplanting pig corneas into people, once it gets government approval. And at Massachusetts General Hospital, researchers announced in October that they had used gene-edited pig skin as a temporary wound covering for a person with severe burns. The skin patch, they say, worked as effectively as human skin, which is much harder to obtain.

But when it comes to life-or-death organs, like hearts and livers, transplant surgeons still must rely on human parts. One day, the dream goes, genetically modified pigs like this sow will be sliced open, their hearts, kidneys, lungs and livers sped to transplant centers to save desperately sick patients from death.

In the outskirts of Munich, Germany, researchers at the Center for Innovative Medical Models Facility of Ludwig-Maximilians University are breeding genetically modified pigs, hoping to eventually use organs from their descendants for human transplants. Laetitia Vancon

The death of Baby Fae

Today in the United States, 7,300 people die each year because they can’t find an organ donor—two-thirds of them for want of a kidney. In many cases, the only hope is someone else’s tragedy: an accident that kills someone whose organs can be harvested.

Surgeons looking for another source of organs at first looked to monkeys, because they’re the animals most similar to us. In 1984, a little girl known as Baby Fae received a baboon heart but died 20 days later, after her immune system attacked it. Baby Fae’s short life and quick death received global attention; many condemned the idea of killing our closest animal relatives to save ourselves. An opinion piece by a cardiologist in the Washington Post described the procedure as “medical adventurism.” Another, in the Journal of Medical Ethics, was headlined “Baby Fae: A beastly business.”