The award-winning New York Times science writer Carl Zimmer.
Carl Zimmer, the award-winning New York Times science writer, recently published a stellar book about human heredity called "She Has Her Mother's Laugh." Truly a magnum opus, the book delves into the cultural and scientific evolution of genetics, the field's outsize impact on society, and the new ways we might fundamentally alter our species and our planet.
"I was only prepared to write about how someday we would cross this line, and actually, we've already crossed it."
Zimmer spoke last week with editor-in-chief Kira Peikoff about the international race to edit the genes of human embryos, the biggest danger he sees for society (hint: it's not super geniuses created by CRISPR), and some outlandish possibilities for how we might reproduce in the future. This interview has been edited and condensed for clarity.
I was struck by the number of surprises you uncovered while researching human heredity, like how fetal cells can endure for a lifetime in a mother's body and brain. What was one of the biggest surprises for you?
Something that really jumped out for me was for the section on genetically modifying people. It does seem incredibly hypothetical. But then I started looking into mitochondrial replacement therapy, so-called "three parent babies." I was really surprised to discover that almost by accident, a number of genetically modified people were created this way [in the late 90s and early 2000s]. They walk among us, and they're actually fine as far as anyone can tell. I was only prepared to write about how someday we would cross this line, and actually, we've already crossed it.
And now we have the current arms race between the U.S. and China to edit diseases out of human embryos, with China being much more willing and the U.S. more reluctant. Do you think it's more important to get ahead or to proceed as ethically as possible?
I would prefer a middle road. I think that rushing into tinkering with the features of human heredity could be a disastrous mistake for a lot of reasons. On the other hand, if we completely retreat from it out of some vague fear, I think that we won't take advantage of the actual benefits that this technology might have that are totally ethically sound.
I think the United Kingdom is actually showing how you can go the middle route with mitochondrial replacement therapy. The United States has just said nope, you can't do it at all, and you have Congressmen talking about how it's just playing God or Frankenstein. And then there are countries like Mexico or the Ukraine where people are doing mitochondrial replacement therapy because there are no regulations at all. It's a wild west situation, and that's not a good idea either.
But in the UK, they said alright, well let's talk about this, let's have a debate in Parliament, and they did, and then the government came up with a well thought-through policy. They decided that they were going to allow for this, but only in places that applied for a license, and would be monitored, and would keep track of the procedure and the health of these children and actually have real data going forward. I would imagine that they're going to very soon have their first patients.
As you mentioned, one researcher recently traveled to Mexico from New York to carry out the so-called "three-parent baby" procedure in order to escape the FDA's rules. What's your take on scientists having to leave their own jurisdictions to advance their research programs under less scrutiny?
I think it's a problem when people who have a real medical need have to leave their own country to get truly effective treatment for it. On the other hand, we're seeing lots of people going abroad to countries that don't monitor all the claims that clinics are making about their treatments. So you have stem cell clinics in all sorts of places that are making all sorts of ridiculous promises. They're not delivering those results, and in some cases, they're doing harm.
"Advances in stem cell biology and reproductive biology are a much bigger challenge to our conventional ideas about heredity than CRISPR is."
It's a tricky tension for sure. Speaking of gene editing humans, you mention in the book that one of the CRISPR pioneers, Jennifer Doudna, now has recurring nightmares about Hitler. Do you think that her fears about eugenics being revived with gene editing are justified?
The word "eugenics" has a long history and it's meant different things to different people. So we have to do a better job of talking about it in the future if we really want to talk about the risks and the promises of technology like CRISPR. Eugenics in its most toxic form was an ideology that let governments, including the United States, sterilize their own citizens by the tens of thousands. Then Nazi Germany also used eugenics as a justification to exterminate many more people.
Nobody's talking about that with CRISPR. Now, are people concerned that we are going to wipe out lots of human genetic diversity with it? That would be a bad thing, but I'm skeptical that would actually ever happen. You would have to have some sort of science fiction one-world government that required every new child to be born with IVF. It's not something that keeps me up at night. Honestly, I think we have much bigger problems to worry about.
What is the biggest danger relating to genetics that we should be aware of?
Part of what made eugenics such a toxic ideology was that it was used as a justification for indifference. In other words, if there are problems in society, like a large swath of people who are living in poverty, well, there's nothing you can do about it because it must be due to genetics.
If you look at genetics as being the sole place where you can solve humanity's problems, then you're going to say well, there's no point in trying to clean up the environment or trying to improve human welfare.
A major theme in your book is that we should not narrow our focus on genes as the only type of heredity. We also may inherit some epigenetic marks, some of our mother's microbiome and mitochondria, and importantly, our culture and our environment. Why does an expanded view of heredity matter?
We should think about the world that our children are going to inherit, and their children, and their children. They're going to inherit our genes, but they're also going to inherit this planet and we're doing things that are going to have an incredibly long-lasting impact on it. I think global warming is one of the biggest. When you put carbon dioxide into the air, it stays there for a very, very long time. If we stopped emitting carbon dioxide now, the Earth would stay warm for many centuries. We should think about tinkering with the future of genetic heredity, but I think we should also be doing that with our environmental heredity and our cultural heredity.
At the end of the book, you discuss some very bizarre possibilities for inheritance that could be made possible through induced pluripotent stem cell technology and IVF -- like four-parent babies, men producing eggs, and children with 8-celled embryos as their parents. If this is where reproductive medicine is headed, how can ethics keep up?
I'm not sure actually. I think that these advances in stem cell biology and reproductive biology are a much bigger challenge to our conventional ideas about heredity than CRISPR is. With CRISPR, you might be tweaking a gene here and there, but they're still genes in an embryo which then becomes a person, who would then have children -- the process our species has been familiar with for a long time.
"We have to recognize that we need a new language that fits with the science of heredity in the 21st century."
We all assume that there's no way to find a fundamentally different way of passing down genes, but it turns out that it's not really that hard to turn a skin cell from a cheek scraping into an egg or sperm. There are some challenges that still have to be worked out to make this something that could be carried out a lot in labs, but I don't see any huge barriers to it. Ethics doesn't even have the language to discuss the possibilities. Like for example, one person producing both male and female sex cells, which are then fertilized to produce embryos so that you have a child who only has one parent. How do we even talk about that? I don't know. But that's coming up fast.
We haven't developed our language as quickly as the technology itself. So how do we move forward?
We have to recognize that we need a new language that fits with the science of heredity in the 21st century. I think one of the biggest problems we have as a society is that most of our understanding about these issues largely comes from what we learned in grade school and high school in biology class. A high school biology class, even now, gets up to Mendel and then stops. Gregor Mendel is a great place to start, but it's a really bad place to stop talking about heredity.
[Ed. Note: Zimmer's book can be purchased through your retailer of choice here.]
A drone hovers over Tacuarembó hospital in Uruguay, carrying its precious cargo: breast milk intended for children in remote parts of the country.
But these children need breast milk throughout their first six months, if not longer, to prevent malnutrition and other illnesses that are prevalent in rural Tacuarembó. Ground transport isn't quick or reliable enough to meet this goal. It can take several hours, during which the milk may spoil due to a lack of refrigeration.
The battery-powered drones have been the difference-maker. The project to develop them, financed by the UNICEF Innovation Fund, is the first of its kind in Latin America. To Castelli, it's nothing short of a revolution. Tacuarembó Hospital, along with three rural clinics in the most impoverished part of Uruguay, are its leaders.
"This marks the first occasion when the public health system has been directly impacted [by our technology]," says Sebastián Macías, the CEO and co-founder of Cielum, an engineer at the University Republic, which collaborated on the technology with a Uruguayan company called Cielum and a Swiss company, Rigitech.
The drone can achieve a top speed of up to 68 miles per hour, is capable of flying in light rain, and can withstand winds of up to 30 miles per hour at a maximum altitude of 120 meters.
"We have succeeded in embracing the mothers from rural areas who were previously slipping through the cracks of the system," says Ferreira, the hospital director. He envisions an expansion of the service so it can improve health for children in other rural areas.
Nurses load the drone for breast milk delivery.
Sebastián Macías - Cielum
The star aircraft
The drone, which costs approximately $70,000, was specifically designed for the transportation of biological materials. Constructed from carbon fiber, it's three meters wide, two meters long and weighs 42 pounds when fully loaded. Additionally, it is equipped with a ballistic parachute to ensure a safe descent in case the technology fails in midair. Furthermore, it can achieve a top speed of 68 miles per hour, fly in light rain, and withstand winds of 30 miles per hour at a height of 120 meters.
Inside, the drones feature three refrigerated compartments that maintain a stable temperature and adhere to the United Nations’ standards for transporting perishable products. These compartments accommodate four gallons or 6.5 pounds of cargo. According to Macías, that's more than sufficient to carry a week’s worth of milk for one infant on just two flights, or 3.3 pounds of blood samples collected in a rural clinic.
“From an energy perspective, it serves as an efficient mode of transportation and helps reduce the carbon emissions associated with using an ambulance,” said Macías. Plus, the ambulance can remain available in the town.
Macías, who has led software development for the drone, and three other technicians have been trained to operate it. They ensure that the drone stays on course, monitor weather conditions and implement emergency changes when needed. The software displays the in-flight positions of the drones in relation to other aircraft. All agricultural planes in the region receive notification about the drone's flight path, departure and arrival times, and current location.
The future: doubling the drone's reach
Forty-five days after its inaugural flight, the drone is now making five flights per week. It serves two routes: 34 miles to Curtina and 31 miles to Tambores. The drone reaches Curtina in 50 minutes while ambulances take double that time, partly due to the subpar road conditions. Pueblo Ansina, located 40 miles from the state capital, will soon be introduced as the third destination.
Overall, the drone’s schedule is expected to become much busier, with plans to accomplish 20 weekly flights by the end of October and over 30 in 2024. Given the drone’s speed, Macías is contemplating using it to transport cancer medications as well.
“When it comes to using drones to save lives, for us, the sky is not the limit," says Ciro Ferreira, Tacuarembó hospital director.
In future trips to clinics in San Gregorio de Polanco and Caraguatá, the drone will be pushed to the limit. At these locations, a battery change will be necessary, but it's worth it. The route will cover up to 10 rural Tacuarembó clinics plus one hospital outside Tacuarembó, in Rivera, close to the border with Brazil. Currently, because of a shortage of ambulances, the delivery of pasteurized breast milk to Rivera only occurs every 15 days.
“The expansion to Rivera will include 100,000 more inhabitants, doubling the healthcare reach,” said Ferreira, the director of the Tacuarembó Hospital. In itself, Ferreira's hospital serves the medical needs of 500,000 people as one of the largest in Uruguay's interior.
Alejandro Del Estal, an aeronautical engineer at Rigitech, traveled from Europe to Tacuarembó to oversee the construction of the vertiports – the defined areas that can support drones’ take-off and landing – and the first flights. He pointed out that once the flight network between hospitals and rural polyclinics is complete in Uruguay, it will rank among the five most extensive drone routes in the world for any activity, including healthcare and commercial uses.
Cielum is already working on the long-term sustainability of the project. The aim is to have more drones operating in other rural regions in the western and northern parts of the country. The company has received inquiries from Argentina and Colombia, but, as Macías pointed out, they are exercising caution when making commitments. Expansion will depend on the development of each country’s regulations for airspace use.
For Ferreira, the advantages in Uruguay are evident: "This approach enables us to bridge the geographical gap, enhance healthcare accessibility, and reduce the time required for diagnosing and treating rural inhabitants, all without the necessity of them traveling to the hospital,” he says. "When it comes to using drones to save lives, for us, the sky is not the limit."