How Scientists in Britain Are Deciding the Future of Humanity

Gene editing amniotic sac
A human embryo in amniotic sac at the ninth week of gestation. Dea/ L. Ricciardini/De Agostini/Getty

Layla Richards was a bouncy 7 pound, 10 ounce baby with downy dark hair and plump cheeks when she was born in a London hospital in June 2014. But 12 weeks later, Layla, who had been settling in at home in North London, suddenly stopped drinking milk and began to fuss and cry constantly. Because she had been a sunny, happy infant until then, her parents took her to see the doctor. He suspected a stomach bug, but just to be sure he took a blood test. The results that came a few days later were a shock: Layla had an acute, deadly form of leukemia that she couldn't survive without immediate treatment. She was just 14 weeks old.

When the diagnosis came in, an ambulance rushed the family from their home to intensive care at the Great Ormond Street (GOS) Hospital, the world-famous pediatric center in Bloomsbury. Her doctors described her cancer as "one of the most aggressive forms of the disease" they had ever seen. For the next few weeks, she endured several rounds of chemotherapy, followed by a full bone marrow transplant to replace her damaged blood cells. This sort of aggressive therapy can often be successful in babies, but none of Layla's treatments, even the experimental ones, worked. Medically, she was out of options. Only one choice remained—admitting her to an end-of-life care facility to make her final weeks more comfortable.

Just a few doors down from the leukemia ward at Great Ormond Street Hospital is the office of Dr. Waseem Qasim, a bearded, genial immunologist who specializes in immune system disorders in children, including cancers. For several months, Qasim had been working on a new type of leukemia treatment in which an anonymous donor's white blood cells are engineered to recognize cancer cells, by tweaking their genes. White blood cells are the body's soldiers; they fight infectious disease and foreign invaders. The engineered cells form an arsenal of targeted cancer-killer cells that can be injected into anyone. There was one problem: The procedure had only been tested in mice.

Qasim's lab is based in the University College London GOS Institute of Child Health, which is connected by a single corridor to Great Ormond Street. "We move effortlessly between the two. There are no other physical or intellectual barriers, so it leads to serendipitous events," Qasim says, as we stroll through a set of double doors from his lab into the hospital. Qasim heard about Layla's case from her transplant surgeon. "He asked as a sort of joke, 'I might be out of my mind but could [your cells] be useful here?'" Qasim recalls.

Doctors at London's Great Ormond Street Hospital managed to reverse a previously incurable form of leukemia in Layla Richards (pictured), using an innovative gene editing technique. She is now healthy. Great Ormand Street Hospital

Because the therapy had never before been tested in humans, there was the obvious danger of things going badly wrong, but Layla's parents and doctors knew she would die without a miracle. After the Medicines and Healthcare products Regulatory Agency granted an emergency license, Layla became the first person in the world to receive a single vial of gene-edited cells from a stranger to attack her cancer.

What followed after Qasim's experimental gene treatment, a new technique using custom-designed molecular scissors to cut, edit and delete DNA, was described by Layla's doctors as "miraculous" and "staggering." She went into remission within four weeks and successfully survived a second bone marrow transplant. Now, nearly two years on, she remains healthy and cancer-free.

Who Wants to Play God?

Little Layla was a pioneer, the first person saved by gene editing; and without the favorable environment created by British scientists and regulators over the past decade, Qasim's experimental treatment, which gives special properties to cells, would never have been allowed.

With recent advances in gene editing and governmental approvals, the U.K. is set to become the unlikely pioneer in one of the most controversial, yet astonishing spheres of human knowledge: the manipulation of our genetic code. While research labs around the world are working on genetic cures to childhood and adult diseases, most have been wary of interfering with the DNA of a human embryo, fearful of unintended consequences for future generations.

Yet the U.K. achieved a double first in 2016: It became the first country to legally permit replacing part of an embryo with a third person's genes, and the first to allow genetic modification in humans from the embryo stage.

Opponents of the techniques, including the U.S. National Institutes of Health (NIH) as well as bioethicists and religious leaders, believe they herald a dystopian future of "designer babies"—a world where parents will "play God" by opting to edit their unborn child's genes to make it stronger, taller and healthier. Molecular biologist and ethicist David King, the founder of British watchdog group Human Genetics Alert, believes that embryo manipulation opens up "for the first time in human history, the possibility of consciously designing human beings, in a myriad of different ways." A recent report from the Nuffield Council on Bioethics in London found that gene editing—particularly in embryos—demanded further scrutiny. Ethical opposition has arisen especially where, it said, the "scope for unforeseen consequences is considered to be great or editing is regarded as irreversible."

Read more: In latest CRISPR discovery, scientists find new way to edit RNA

All humans have a unique "genome" sequence, the more than 3 billion molecule pairs known as DNA that define who we are, from our physical appearance to biological characteristics and even our personality. Our hair color, our preference for certain kinds of food even our ability to make deadlines—it's all rooted in our DNA. Mutations or mistakes in this genetic code can result in disease, such as diabetes or leukemia. Gene editing means we can now find and correct genetic errors in a lab. Once honed, the tools could be used to fix maladies like sickle cell anemia and cystic fibrosis and even fight cancer.

The promise of gene editing goes beyond curing adult disease—it could even be used to modify human embryos and delete egregious genetic defects before birth. That would prevent the transmission of debilitating illnesses from parent to child, and could signal the end of devastating inherited disabilities.

The British government's recent endorsement of gene editing research thrust the country to the forefront of the next revolution in health and science, whether the rest of the world is ready for it or not.

Louise Brown, shown on July 25, 1978, was born at Oldham Hospital near Manchester, England. She was the first "test tube baby" born as a result of in vitro fertilization. Keystone-France/Gamma-Keystone/Getty

Gene Genies

Nearly four decades before Layla Richards was born, another baby girl made history in Britain. In July 1978, Louise Brown was born by Caesarean section to very eager parents. There was nothing particularly unusual about the birth of this healthy, 5-pound-12-ounce baby—and yet her arrival into the world helped two British scientists win a Nobel Prize. The reason: Louise was conceived in a petri dish, the world's first baby created through the process of in vitro fertilization (IVF). Back then, Louise was called the first "test-tube baby," an indication of how bizarre the now-standard procedure was considered at the time. In 1981, The New York Times wrote that the procedure was considered "equivalent to abortion in the eyes of some opponents."

Louise's immaculate-lab conception is part of the U.K.'s long history of developing groundbreaking biotech. That legacy began at the University of Cambridge in 1953, when doctoral students Francis Crick and James Watson cracked DNA's double-helix structure, forever reshaping our understanding of human biology. The simple two-strand configuration—drawn by hand by Crick's wife Odile in their original Nature paper—gave rise to the entire field of modern molecular biology, and it spawned cutting-edge techniques from cloning to gene editing. British researchers have pioneered clinical techniques in reproductive biology, including IVF, the discovery of embryonic stem cells in mice (1981) and the first cloning of a mammal, Dolly the sheep (1996).

Read more: GMO scientists could save the world from hunger, if we let them

With each of these milestones, scientists around the world faced a moral dilemma concerning the definition of human life. When does a ball of cells become a fetus? Does an artificially created life form have rights? Should physical impairments like deafness be culled from our population? After the birth of Louise Brown, the British government convened an ethical committee headed by philosopher Mary Warnock to investigate the implications of creating and modifying human life in a lab. The resulting report, published in 1987, led to a nationwide consensus on the obvious social benefits of IVF.

The report also led to the establishment of the Human Fertilization and Embryology Authority (HFEA), the first independent legislative body in the world to regulate human embryo research and IVF treatment. It is overseen by an independent board rather than government ministers, but is sponsored by the British Department of Health, whose head appoints the board. Members include geneticists, philosophers, former civil servants and finance and business professionals. The chair, Sally Cheshire, reports directly to the U.K.'s minister for health. The HFEA is a symbol of Britain's commitment to innovation in medical science—unique in its progressive nature, compared to other advanced nations like the U.S. and Germany, where religion and politics often hold back research.

HFEA recently granted two controversial licenses: In February 2015, the British government approved a pioneering gene technology to prevent potentially fatal mitochondrial disease from passing from mother to child. By placing a donor's healthy genes in an IVF embryo, the researchers say the resulting baby could avoid severe symptoms such as deafness, muscle withering, liver or kidney failure and brain damage. But critics worry that when these babies pass on the new genetic code to their children, grandchildren and every subsequent generation, there will be as-yet-unknown consequences.

Despite vocal opposition from a smattering of members of Parliament, as well as challenges from the Church of England and the Catholic clergy, the British House of Commons voted by an overwhelming majority to allow this mitochondrial donation.

And although the process has the U.K. government's stamp of approval, it is not approved as safe and effective by the U.S. or Chinese authorities. In a review of the technology earlier this year, the U.S. Food and Drug Administration warned that the evidence does not yet support the safe use of mitochondrial transfer in humans.

In February 2016, geneticist Kathy Niakan of the U.K.'s Francis Crick Institute became the first scientist in the world to receive a license to edit healthy human embryos for research. (The embryos cannot be implanted into a human.) Her goal is to better understand the process of early human development, not redesign babies. Even so, some lawmakers were determined to prevent this sort of research in Britain. In a parliamentary debate about the license, Conservative Party parliamentarian Jacob Rees-Mogg said: "In a country nervous about genetically modified crops, we are making the foolhardy move to genetically modified babies."

Key figures at the U.S. National Institutes of Health have similar concerns. At a gathering of scientific experts who convened in July to discuss the implications of gene editing, NIH Director Francis Collins underlined his agency's reluctance to fund research into modification of human embryos because of ethical concerns.

Collins has acknowledged that his religious beliefs prevent him from backing gene modification in human embryos. "I do believe that humans are in a special way individuals and a species with a special relationship to God, and that requires of a great deal of humility about whether we are possessed of enough love and intelligence and wisdom to start manipulating our own species," he said in a recent interview with Buzzfeed News.

The U.S. bans the use of federal funding for any human embryo research. The law, which was passed by Congress in 1995, says federal funding would not be available for any "research in which a human embryo or embryos are destroyed, discarded or knowingly subjected to risk of injury or death greater than that allowed for research on fetuses in utero."

"It's very difficult to have a real debate about any issues to do with artificial conception technology or gene manipulation there because everyone is scared the argument will become about abortion, which they don't want to raise up against," says professor Robin Lovell-Badge, a scientific adviser to HFEA and the U.S. National Academy of Sciences on issues of gene editing. "The debate is dominated by political and religious groups. It creates a nervousness [in the U.S.] which in the U.K. we don't have, because we know exactly where the barriers are; they are set out by law and detailed regulations."

Read more: U.S. lawmakers say no to embryo gene editing

Despite its qualms about embryo research, the U.S. federal government does permit IVF treatments. "Ironically, [the NIH] supports IVF, which relies on human embryo research to keep it current, so they are relying on research done in other countries but won't support it themselves," Niakan tells Newsweek. "It doesn't make any sense whatsoever."

Niakan, along with Lovell-Badge, became the first cohort of scientists at the newly opened Francis Crick Institute in London—named in honor of the renowned Briton, and the very first research hub to be granted an HFEA license to edit seven-day-old living human embryos. Their work will focus on helping improve the success rates of IVF, the technique successfully demonstrated just some 200 miles north, when Louise Brown was born in 1978.

Louise Brown at the age of 3 in January, 1981, in the United Kingdom. Michel Artault/Gamma-Rapho/Getty

Every Conception a Miracle

Headed by Nobel Prize–winning biologist Sir Paul Nurse, Francis Crick's eponymous research institution opened in September. It's an imposing edifice with glass atria and a distinctive vaulted roof, mirroring the nearby St. Pancras International train station. With an investment of about $805 million and known to insiders as Sir Paul's Cathedral, the building will house 1,250 scientists in four interconnected blocks, making it the largest biomedical research institute in Europe. Within its corridors, British scientists will be the first people ever to glimpse the molecular mysteries that result in the conception of human life.

The woman at the vanguard of this effort is 38-year-old Niakan, petite and dark-haired, with a birdlike face. When she greets me in May in her temporary lab in the Mill Hill neighborhood of north London she could easily be mistaken for an undergraduate in her leggings and knitted jumper.

As she describes what an early human embryo—or blastocyst—looks like on Day Five of its existence, she grabs a scrap of paper and begins to sketch. Every so often, she punctuates the illustration with circled numbers to show the low survival rate of IVF embryos: Only 40 percent of fertilized embryos become blastocysts, of which only 50 percent will implant in a woman's uterus. Another 50 percent, she says, fail to make it past three months of development. Right now, we have little idea why embryos fail so often. When I point out that, statistically, it seems miraculous that humans have been reproducing successfully for centuries, she exclaims, "I know, right?"

The daughter of Iranian immigrants, Niakan grew up in the small town of Silverdale, Washington, where her father was a practicing neurologist. She became interested in genetics as a first-year student at the University of Washington in Seattle, where she begged to be allowed to wash dishes in a lab that studied congenital diseases in large families; the lab allowed her to assist researchers studying human genetics, and she eventually discovered the gene responsible for a type of thalassemia, a genetic blood disorder. "I remember being in a genetics class and there was the textbook view of all the different DNA bands, and then I was in the lab, physically, I was literally reading out, 'That's an A. That's a T. That's a G, C.' I just loved it," Niakan says, recalling her earliest experiences of DNA sequencing. "I was hooked, and since then I haven't stopped."

Niakan has studied developmental biology at the University of California, Harvard University and the University of Cambridge in the U.K., where she moved in 2009 as a postdoctoral fellow. "I really love trying to understand how you go from a single-celled organism to this really complicated set of three distinct cell types that are very set in their ways. That's in fact the same question I'm still asking many years later," she says. "The U.K. has very proactive ways of approaching reproductive health and medicine—it's brilliant and it's the reason why I've stayed for so long."

A scientist performs research at the Francis Crick Institute in London. Fiona Hanson

Niakan's goal is to understand the earliest stages of a human life, when we are nothing but a ball of 200 cells. She knows her work could ultimately help women to conceive and genetic diseases to be defeated, but that is not what drives her. Her real motivation is cracking the scientific mystery of human reproduction. "It has the potential to really revolutionize our understanding of human biology in a petri dish," she says. "That's fascinating to me." Using a gene-editing tool called CRISPR-Cas 9 (pronounced "crisper") that can cut and edit DNA very precisely, she wants to isolate genes thought to be important for fetal development; only then can we figure out exactly what role each plays. "This basic biological question—Which genes are critically required?—is important because it can help us understand which blastocysts will go on to develop, implant and thrive."

Today, when a woman comes in to a clinic for IVF treatment, experts score her embryo quality based on physical shape, size and other visible features, rather than genetic features. Although embryos can be screened for chromosomal abnormalities, little is known about human developmental genetics at this early stage. "There are very few molecular tools used to identify those embryos. We know there's a 50 percent drop-off rate, so I think there's room to determine the key signatures that embryos need to successfully implant," Niakan says. "It could increase the chances [of pregnancy], or it could help to choose those embryos that will likely go on to develop successfully into a healthy baby." Eventually, the knowledge could help us fathom causes of reproductive defects or even infertility.

The HFEA spent three years investigating Niakan's request to use the CRISPR-Cas9 scissors, conducting a series of detailed inspections of her lab work, including whether embryos were handled respectfully and carefully in the lab, and if donors were counseled and updated appropriately. Niakan was notified of their decision in late January. The overwhelming feeling wasn't excitement or even elation, she says; she had just been afraid that irrationality and fear of the unknown would win out over science.

The decision was celebrated by scientists, patient groups with genetic diseases and mothers who had struggled to conceive. Emma Benjamin, a 34-year-old woman who miscarried four times spoke widely to the press of her support. "I found it frustrating I never had answers as to why I kept miscarrying," she said. "If this research had come earlier and could have helped me provide answers then I guess, you know, it could have maybe saved a lot of heartache."

Francis Crick institute
A view outside the new Francis Crick Institute building in central London on September 1, 2016. The new £650 million Francis Crick Institute will be the biggest biomedical research institute under one roof in Europe. DANIEL LEAL-OLIVAS/AFP/Getty

Baby Steps

Despite Niakan's momentous victory, it remains illegal in the U.K. to implant genetically modified embryos into a womb for the purpose of giving birth. That ensures that modified genes are not passed onto future generations; Niakan's lab must destroy every embryo after the seven-day mark.

Although Niakan insists this research has no bearing on actual babies (for now), many in the scientific community are considering the possibility that a modified embryo could result in a living child. In December 2015, several hundred scientists from around the world gathered in Washington, D.C., for the first ever international summit on gene editing. At its close, the event chair and Nobel Prize–winning biologist David Baltimore, of the California Institute of Technology, issued its conclusions, saying, "As scientific knowledge advances and societal views evolve, the clinical use of germline [embryo] editing should be revisited on a regular basis."

The scientists have reason to be anxious: Some of their brethren have raced ahead already. In April 2015, researchers in Guangzhou, China, announced they had conducted a CRISPR gene-modification experiment on defective human embryos, to edit the gene responsible for beta-thalassaemia, a potentially fatal blood disorder. It was a resounding failure, because the CRISPR method accidentally edited the wrong genes, which ended up irreversibly scrambling the embryo's DNA.

That research sparked a hot global debate in the academic fraternity about whether to declare a moratorium on embryo modification until ethical laws and regulations could catch up with science. In response, scientists from the United States, Britain and China at the Washington summit called for a temporary freeze on altering human embryos destined for birth, calling it "irresponsible" and potentially dangerous. The quick decision to cooperate internationally speaks to the transnational nature of this research; this is a strand of science that could change what it means to be human.

Read more: We need to talk about human genetic engineering before it's too late

Even gene editing's strongest proponents acknowledge that there could be catastrophic mistakes. For instance, CRISPR could edit genes inaccurately, causing unintended mutations and disfigurations. There's also the very real risk of rogue editing by malicious parties— wealthy people paying for genetic enhancements, which could become a form of social discrimination and could introduce novel genetic sequences into the species—a sort of genetic cosmetic surgery. Until these safety and ethical issues have been resolved, the scientific community proposed holding back, and re-assessing current research on a constant basis.

Rumors of several other Chinese experiments on human embryos in academic circles sparked worries of an unregulated black market of clinical research. In a parallel case, the U.S. has no laws governing private research on embryos despite federal funding sanctions, meaning embryos end up being traded like contraband. "There's a billion-dollar IVF enterprise in private clinics, many of whom are using techniques that are dubious to say the least," Lovell-Badge says. "There are strict rules against implanting more than two embryos in a woman. Yet there are famous cases in the U.S. like the 'Octomom' who had eight babies, where they clearly couldn't have followed any regulations at all."

While most scientists acknowledge that editing embryos will probably be a clinical option one day, some remain staunchly opposed. King, of Human Genetics Alert, refers to gene editing as the "new techno-eugenics."

Scientists perform research at the Francis Crick Institute in London. Fiona Hanson

Lovell-Badge believes frank discussion and public trust in the HFEA is the key to a safe clinical transition. "It is illegal in the U.K. to transfer any gene-edited embryo into a woman," he says. "Given the experience with the way the HFEA regulates [this research], and if the law were to be changed, I expect the public could also be reassured that any applications would be restricted to important clinical uses."

Niakan agrees, pointing to U.K. regulators' ability to separate church and state in the matter of controversial scientific research such as hers. "The UK's pioneering role in advancing reproductive medicine and health, especially IVF, has a lot has to do with the regulatory framework, where people are willing to engage in frank discussions about these complex issues," Niakan says. "In other countries the message gets muddled up with politics and religion."

Editing for the Perfect Baby

Although embryo editing remains firmly confined to laboratories, scientists at Newcastle University in the north of England are taking the next step into the future by genetically modifying IVF embryos to create healthy babies.

In September, the world's first baby with three people's genes was born in Mexico, to Jordanian parents who had lost two children and had four miscarriages due to mitochondrial disease. The genetic illness is caused by dysfunctional mitochondria, the cellular units that are responsible for generating energy. In the case of this baby, the malfunction was caused by mutations, or errors, in the mitochondrial DNA. The procedure was performed by a team of doctors from New York City, although details on how it was done are scant. The only country with any legal or regulatory framework for the technology is the U.K, where—as of December 2016—an embryo can legally be modified, and implanted into a woman's uterus.

Until Rachel Steel turned 20, she knew almost nothing about IVF regulations and cared even less. She competed as a gymnast as a child, studied pediatric nursing at Northumbria University in Newcastle and taught gym to kids in her neighborhood. She wanted to have children before she was 30, but was in no hurry. The only health problems she'd ever encountered were ear infections—which caused a slight difficulty in hearing—she often had them growing up and tended to compensate by lipreading. Doctors could never quite pinpoint the cause of her ear problems. But five years ago, Steel learned she had a genetic mutation in her mitochondrial DNA.

Doctors at the Royal Victoria Infirmary in Newcastle, where Steel, 26, works as a nurse, first suspected something odd when her mother was brought in for a pancreatic transplant, following a kidney transplant some years before. "They realized that all of her five siblings had diabetes and some mild deafness and found it strange," she says. When they did a genetic test, they found Steel's mother had mitochondrial disease. Since mitochondria are passed on exclusively from mother to child, her daughters had inherited her mutation.

The vast majority of your 20,000 genes are found in the nucleus of each of your cells, which contains DNA from both your parents, but mitochondria have their own genome, which carries only about 37 genes and is inherited from your mother alone. The severity of mitochondrial disease depends on the fraction of mutations in the 37 genes inherited; in Steel's case, the news was not good. She had inherited 80 percent of her mother's mutations. Steel remains mostly healthy so far, but her disease could progress to anything from diabetes to full-blown hearing loss, or extreme muscle deterioration.

If Steel has children, they could be even more severely afflicted. "When I was younger, I thought, Oh, it affects babies, that's bad. But I didn't think it actually applied to me," Steel says. About one in 200 babies in the U.K. are born with mitochondrial disease. In the U.S., the percentage is lower at roughly one in 1,000 afflicted babies born every year; many only live a few hours, while others begin to rapidly sicken after a few years, suffering from brain, heart or kidney disease. There is no cure for mitochondrial disease. For women who have the condition and want to have children, the only options are to get pregnant and then screen out affected embryos—a heartbreaking process for would-be parents—or have an IVF baby using a donor egg.

Obama Klepper
U.S. President Barack Obama greets 11-year-old Haley Klepper during a ceremony honoring the 2012 NCAA Women’s College Basketball Champion Baylor Bears in the East Room of the White House in Washington, DC, July 18, 2012. The team's so-called biggest fan, Klepper, who suffers from a rare mitochondrial disease, attends all the team's games and has a reserved spot in the locker room. SAUL LOEB/AFP/Getty

The man fighting hardest for Steel's future is her 64-year-old doctor, Sir Douglass Turnbull, who has been specializing in mitochondrial disease for 35 years. "Several of my patients I've known for 20 or 30 years, along with their entire families," he tells Newsweek in his lab at Newcastle University. "There can be three generations in a family that are affected, many of whom lose three or four children due to the disease. For me, that's the biggest motivation."

Since 2001, Turnbull, along with Newcastle embryologist Mary Herbert, has been working on a new IVF technique, known as mitochondrial donation, that offers women like Steel—2,500 of whom have been identified in the U.K. alone—a way to have biological children who do not have the mother's mutations. The technique is a bit like swapping the yolk of an egg: It involves removing a healthy nucleus, or yolk, of the mother's fertilized egg which contains about 99.8 percent of genetic material that the child will inherit. This is transferred into the egg of a donor that has had its nucleus removed. The donor, who does not have mitochondrial disease, will pass on her healthy mitochondria. This way the baby will inherit the vast majority of its biological characteristics from its parents via its nuclear DNA, but will have the healthy mitochondrial genes of the donor.

In a paper published in Nature this past summer, Turnbull and Herbert found that their technique could reduce the risk of passing on defective mitochondrial DNA to under 5 percent, far better than the 60 to 90 percent risk otherwise. "For people who just watch their child fall apart before their eyes, this is a hugely positive outcome," says Herbert.

The Newcastle-based scientists started lobbying the HFEA to approve their technique in 2012, and came up against intense opposition. Because the mitochondrial transfer method passes on genetic change from one generation to another, British MPs and even some scientists worried that it could give rise to unexpected problems. Catholic Church ethicists were also opposed to the introduction into an embryo of a third person's genes, arguing that this "dilutes parenthood." The Newcastle team argues that since the donor remains anonymous and has no rights over the child, she shouldn't be considered a third parent.

Other critics are uncomfortable with the idea of deleting disability out of the population completely, believing it would impact on the rights of the handicapped. Bioethicist Tom Shakespeare, who has dwarfism and uses a wheelchair, doesn't believe "fixing" genetic mutations is necessarily what the disabled community wants, although he doesn't oppose mitochondrial donation, in principle. "Contrary to the prevailing assumption, most people with disabilities report a quality of life that is equivalent to that of non-disabled people. Their priority is to combat discrimination and prejudice," he writes in a paper in Nature . Fellow bioethicist and deaf researcher Jackie Leach Scully feels particularly uncomfortable about genetic cures as a solution for all disabilities, although she concedes it would be hard to find anyone opposed to correcting mitochondrial mutations, which are "generally very nasty diseases."

The Newcastle-based scientists strongly object to this reasoning—they believe every mother with genetic disease should have a choice between hoping for the best, or using science to screen for a healthy baby. "We are often criticized because we don't value disability. I don't think that at all. I spend my whole life looking after disabled people but people should have the right to decide whether or not they want to have disabled children," says Turnbull.

In the U.S., fertility doctors in New Jersey performed a crude version of this technique in the 1990s that led to the births of at least 50 babies in the U.S., Israel, Taiwan and Italy. Many are healthy today, but the federal Food and Drug Administration banned the technique in 2001 because of concerns about unexpected genetic defects and reduced fertility in the women born this way. Since then, several American labs have applied for clinical licenses, just like Turnbull and Herbert, but U.S. regulators have shot them down. "Human-subject research utilizing genetic modification of embryos for the prevention of transmission of mitochondrial disease cannot be performed in the United States in FY 2016," an FDA spokesperson said in a statement.

During the five-year debate in British Parliament over this technique, patients including Steel—even those beyond their reproductive years—went to the House of Commons to add their perspective to the discussion, explaining what they wanted. "I one hundred percent want a family," Steel tells me. "It's not to say I can't go naturally ahead, having children, but there's a huge risk and that's a risk I wouldn't take."

Curing the Incurable

While scientists are still fighting to get approval to test their cutting-edge biomedical techniques before using them on humans, Qasim, the immunologist at UCL, is saving more lives—and saving parents from the ultimate tragedy.

Around Christmas 2015, months after Layla Richards was sent home in remission, Qasim's team obtained a second emergency license to treat another baby girl with the identical type of leukemia, which had been diagnosed when the girl was just 4 weeks old. When she was 16 months old, the child (whose parents did not want to make her name public) was given the same dose of gene-edited killer cells Layla received. Weeks later, she was declared cancer-free; now at 2 years 4 months old, she is doing well.

Dr. Waseem Qasim in the Institute for Child Health in central London on November 15, 2016. Dr. Qasim is at the forefront of an exciting new treatment being pioneered at Great Ormond Street Hospital (GOSH) called immunotherapy. Immunotherapy harnesses the patient’s own immune system to improve treatment for children with life-threatening conditions. Abbie Trayler-Smith for Newsweek

Qasim's emergency treatment, which has now saved two children, is part of a larger trial that opened to the public in June. It will treat up to 10 children with the same type of leukemia as the two toddlers who are in remission. If the treatment works for the 10 new patients, the introduction of modified genes could become the primary treatment for cancers like this—supplanting even chemotherapy.

With a slight tweak, Qasim says, this gene therapy could be applied to other cancers, and even genetic diseases like thalassemia. Gene therapies are already being tested for those conditions, so the timeline for fixing a wide range of genetic defects could be as short as five years, he says. The therapy could even be used for diseases considered incurable, like HIV. American pharmaceutical firm Sangamo is running a trial that uses gene editing to engineer the immunity of HIV patients to the disease.

Meanwhile, nearly two years on, Layla remains cancer-free and healthy. At a charity fundraiser for the Great Ormond Street Hospital in December 2015, Layla's mother encouraged other parents with sick children to be unafraid of "guinea pig" treatments, and to "try new things."

If Qasim's therapy is approved for general use, it could be the first of thousands of similar treatments. "Layla has a purpose—to help other people. She was nearly at death's door. You don't normally hear a happy story with cancer," her father said during the appeal. "One day there will be a cure for cancer. Who knows? Maybe in 40 years' time Layla may have helped to make the first step towards that."

Madhumita Murgia is the European technology correspondent at the Financial Times.