There are lots of great reasons we humans have sex. We mostly do it to pair bond, realize our primal urges, and feel good. Once in a while, we also do it to make babies. As the coming genetic revolution plays out, we'll still have sex for most of the same reasons we do today. But we'll increasingly not do it to procreate.
Protecting children from harm is one of the core responsibilities of parenting.
Most parents go to great lengths to protect their children from real and imagined harms. This begins with taking prenatal vitamins during pregnancy and extends to having children immunized and protected from exposures to various diseases and dangers. Most of us look askance for good reason at mothers who abuse controlled substances during their pregnancies or parents who choose to not immunize their children. Protecting children from harm is one of the core responsibilities of parenting.
In the United States today, up to two percent of babies are estimated to be born with rare genetic diseases caused by single gene mutations. Sickle cell disease, Tay-Sachs, and Huntington's disease are among the more well-known examples of these, but the list runs to the thousands. Many babies born with these disorders suffer terribly, some die young, and nearly all spend big chunks of their lives struggling through the medical system.
Increasingly, however, many of these single-gene mutation diseases and other chromosomal disorders like Down syndrome are being identified in non-invasive prenatal tests performed on expectant mothers at the end of their first trimester of pregnancy. Knowing the hardship that children born with these types of disorders will likely face, majorities of these women in countries around the world are choosing to terminate pregnancies once these diagnoses have been made. Whatever the justification and whatever anyone's views on the morality of abortion, these decisions are inherently excruciating.
A much smaller number of prospective mothers, however, are today getting this same information about their potential future children before their pregnancies even begin. By undergoing both in vitro fertilization (IVF) and preimplantation genetic testing (PGT), these women are able to know which of the eggs that have been surgically extracted from them and fertilized with their partner or donor's sperm will carry the dangerous mutations. The in vitro embryos with these disorders are simply not implanted in the expectant mother's womb.
It would be monstrous to assert that an existing person with a deadly disease has any less right to thrive than anyone else. But it would also be hard to make a case that parents should affirmatively choose to implant embryos carrying such a disease if given the option. If prospective parents are already today choosing not to implant certain embryos based on our preliminary understanding of disease risk, what will happen when this embryo selection is based on far more information than just a few thousand single gene mutation diseases?
Our ability and willingness to make genetic alterations to our future children will grow over time along with our knowledge and technological ability.
When the first human genome was sequenced in 2003, the race to uncover the mysteries of human genetics had only just begun. Although we still know very little about our genetics relative to the complexity of the genome and even less compared to the broader ecosystem of our biology, the progress toward greater understanding is astounding. Today, the number of single gene mutation diseases and relatively simple genetic traits that can be predicted meaningfully from genetic data alone is already significant.
In the not-distant future, this list will grow to include complex diseases and disease propensities, percentage probabilities of living a long and healthy life, and increasingly the genetic component of complex human attributes like height, IQ, and personality style. This predictive power of genetic analysis will funnel straight into our fertility clinics where prospective parents choosing embryos will be making ever more consequential decisions about the genetic components of the future lives, health, and capabilities of their children.
Our understanding of what the genes extracted from early stage pre-implanted embryos are telling us will be only one of the rocket boosters driving assisted reproduction forward. Another will be the ability to induce adult cells like skin and nucleated blood cells into stem cells and then turn those stem cells into egg progenitor cells and then ultimately eggs. This will not only eliminate the need for hormone treatments and surgery to extract human eggs but also make it easy and cheap to generate an unlimited number of eggs from a given woman.
The average woman has around fifteen eggs extracted during IVF but imagine what generating a thousand eggs will do to the range of possibilities that could be realized through pre-implantation embryo selection. Each of these thousand eggs would be the natural offspring of the two parents, but the variation between them would make it possible to choose the ones with the strongest expression of the genetic component of a particular desired trait – like those with the highest possible genetic IQ potential.
Another rocket booster will be the application of gene editing technologies like CRISPR to edit the genomes of pre-implanted embryos or of the sperm and eggs used to create them. Just this week, Chinese researchers announced they had used CRISPR to edit the CCR5 gene in the pre-implanted embryos of a pair of Chinese twins to make them immune to HIV, the first ever case of gene editing humans and a harbinger of our genetically engineered future. The astounding complexity of the human genome will put limits on our ability to safely make too many simultaneous genetic changes to human embryos, but our ability and willingness to make these types of alterations to our future children will grow over time along with our knowledge and technological ability.
With so much at stake, prospective parents will increasingly have a stark choice when determining how to conceive their children. If they go the traditional route of sex, they will experience both the benign wisdom and unfathomable cruelty of nature. If they use IVF and increasingly informed embryo selection, they will eliminate most single gene mutation diseases and likely increase their children's chances of living a longer and healthier life with more opportunity than their unenhanced peers. But the optimizing parents could also set up their children for misery if these children don't particularly enjoy what they have been optimized to become or see themselves as some type of freakish consumer product with emotions.
Conceiving though sex will come to be seen more and more like not immunizing your children is today, a perfectly natural choice that comes with a significant potential risk and expense.
But although there will be pros and cons on each side, the fight between conception through good old-fashioned sex and conception in the lab will ultimately not be fair. Differences and competition within and between societies will pressure parents and societies to adopt ever more aggressive forms of reproductive technology if they believe doing so will open possibilities and create opportunities for the next generations rather than close them.
Conception through sex will remain as useful as it has always been but lab conception will only get more advantageous. Over time, only zealots will choose to roll the dice of their future children's health and well-being rather than invest, like parents always have, in protecting their children from harm and helping optimize their life potential. Conceiving though sex will come to be seen more and more like not immunizing your children is today, a perfectly natural choice that comes with a significant potential risk and expense to yourself, your children, and your community.
As this future plays out, the genetics and assisted reproduction revolutions will raise enormous, thorny, and massively consequential questions about how we value and invest in diversity, equality, and our own essential humanity – questions we aren't remotely prepared to answer. But these revolutions are coming sooner than most of us understand or are prepared for so we had better get ready.
Because where this trail is ultimately heading goes well beyond sex and toward a fundamental transformation of our evolutionary process as a species – and that should be everybody's business.
In December 1958, on a vacation with his wife in Kenya, a 28-year-old British tea broker named Robin Cavendish became suddenly ill. Neither he nor his wife Diana knew it at the time, but Robin's illness would change the course of medical history forever.
Robin was rushed to a nearby hospital in Kenya where the medical staff delivered the crushing news: Robin had contracted polio, and the paralysis creeping up his body was almost certainly permanent. The doctors placed Robin on a ventilator through a tracheotomy in his neck, as the paralysis from his polio infection had rendered him unable to breathe on his own – and going off the average life expectancy at the time, they gave him only three months to live. Robin and Diana (who was pregnant at the time with their first child, Jonathan) flew back to England so he could be admitted to a hospital. They mentally prepared to wait out Robin's final days.
But Robin did something unexpected when he returned to the UK – just one of many things that would astonish doctors over the next several years: He survived. Diana gave birth to Jonathan in February 1959 and continued to visit Robin regularly in the hospital with the baby. Despite doctors warning that he would soon succumb to his illness, Robin kept living.
After a year in the hospital, Diana suggested something radical: She wanted Robin to leave the hospital and live at home in South Oxfordshire for as long as he possibly could, with her as his nurse. At the time, this suggestion was unheard of. People like Robin who depended on machinery to keep them breathing had only ever lived inside hospital walls, as the prevailing belief was that the machinery needed to keep them alive was too complicated for laypeople to operate. But Diana and Robin were up for the challenges – and the risks. Because his ventilator ran on electricity, if the house were to unexpectedly lose power, Diana would either need to restore power quickly or hand-pump air into his lungs to keep him alive.
Robin's wheelchair was not only the first of its kind; it became the model for the respiratory wheelchairs that people still use today.
In an interview as an adult, Jonathan Cavendish reflected on his parents' decision to live outside the hospital on a ventilator: "My father's mantra was quality of life," he explained. "He could have stayed in the hospital, but he didn't think that was as good of a life as he could manage. He would rather be two minutes away from death and living a full life."
After a few years of living at home, however, Robin became tired of being confined to his bed. He longed to sit outside, to visit friends, to travel – but had no way of doing so without his ventilator. So together with his friend Teddy Hall, a professor and engineer at Oxford University, the two collaborated in 1962 to create an entirely new invention: a battery-operated wheelchair prototype with a ventilator built in. With this, Robin could now venture outside the house – and soon the Cavendish family became famous for taking vacations. It was something that, by all accounts, had never been done before by someone who was ventilator-dependent. Robin and Hall also designed a van so that the wheelchair could be plugged in and powered during travel. Jonathan Cavendish later recalled a particular family vacation that nearly ended in disaster when the van broke down outside of Barcelona, Spain:
"My poor old uncle [plugged] my father's chair into the wrong socket," Cavendish later recalled, causing the electricity to short. "There was fire and smoke, and both the van and the chair ground to a halt." Johnathan, who was eight or nine at the time, his mother, and his uncle took turns hand-pumping Robin's ventilator by the roadside for the next thirty-six hours, waiting for Professor Hall to arrive in town and repair the van. Rather than being panicked, the Cavendishes managed to turn the vigil into a party. Townspeople came to greet them, bringing food and music, and a local priest even stopped by to give his blessing.
Robin had become a pioneer, showing the world that a person with severe disabilities could still have mobility, access, and a fuller quality of life than anyone had imagined. His mission, along with Hall's, then became gifting this independence to others like himself. Robin and Hall raised money – first from the Ernest Kleinwort Charitable Trust, and then from the British Department of Health – to fund more ventilator chairs, which were then manufactured by Hall's company, Littlemore Scientific Engineering, and given to fellow patients who wanted to live full lives at home. Robin and Hall used themselves as guinea pigs, testing out different models of the chairs and collaborating with scientists to create other devices for those with disabilities. One invention, called the Possum, allowed paraplegics to control things like the telephone and television set with just a nod of the head. Robin's wheelchair was not only the first of its kind; it became the model for the respiratory wheelchairs that people still use today.
Robin went on to enjoy a long and happy life with his family at their house in South Oxfordshire, surrounded by friends who would later attest to his "down-to-earth" personality, his sense of humor, and his "irresistible" charm. When he died peacefully at his home in 1994 at age 64, he was considered the world's oldest-living person who used a ventilator outside the hospital – breaking yet another barrier for what medical science thought was possible.
Sarah Watts is a health and science writer based in Chicago. Follow her on Twitter at @swattswrites.
In June 2012, Kirstie Ennis was six months into her second deployment to Afghanistan and recently promoted to sergeant. The helicopter gunner and seven others were three hours into a routine mission of combat resupplies and troop transport when their CH-53D helicopter went down hard.
Miraculously, all eight people onboard survived, but Ennis' injuries were many and severe. She had a torn rotator cuff, torn labrum, crushed cervical discs, facial fractures, deep lacerations and traumatic brain injury. Despite a severely fractured ankle, doctors managed to save her foot, for a while at least.
In November 2015, after three years of constant pain and too many surgeries to count, Ennis relented. She elected to undergo a lower leg amputation but only after she completed the 1,000-mile, 72-day Walking with the Wounded journey across the UK.
On Veteran's Day of that year, on the other side of the country, orthopedic surgeon Cato Laurencin announced a moonshot challenge he was setting out to achieve on behalf of wounded warriors like Ennis: the Hartford Engineering A Limb (HEAL) Project.
Laurencin, who is a University of Connecticut professor of chemical, materials and biomedical engineering, teamed up with experts in tissue bioengineering and regenerative medicine from Harvard, Columbia, UC Irvine and SASTRA University in India. Laurencin and his colleagues at the Connecticut Convergence Institute for Translation in Regenerative Engineering made a bold commitment to regenerate an entire limb within 15 years – by the year 2030.
Dr. Cato Laurencin pictured in his office at UConn.
Photo Credit: UConn
Regenerative Engineering -- A Whole New Field
Limb regeneration in humans has been a medical and scientific fascination for decades, with little to show for the effort. However, Laurencin believes that if we are to reach the next level of 21st century medical advances, this puzzle must be solved.
An estimated 185,000 people undergo upper or lower limb amputation every year. Despite the significant advances in electromechanical prosthetics, these individuals still lack the ability to perform complex functions such as sensation for tactile input, normal gait and movement feedback. As far as Laurencin is concerned, the only clinical answer that makes sense is to regenerate a whole functional limb.
Laurencin feels other regeneration efforts were hampered by their siloed research methods with chemists, surgeons, engineers all working separately. Success, he argues, requires a paradigm shift to a trans-disciplinary approach that brings together cutting-edge technologies from disparate fields such as biology, material sciences, physical, chemical and engineering sciences.
As the only surgeon ever inducted into the academies of Science, Medicine and Innovation, Laurencin is uniquely suited for the challenge. He is regarded as the founder of Regenerative Engineering, defined as the convergence of advanced materials sciences, stem cell sciences, physics, developmental biology and clinical translation for the regeneration of complex tissues and organ systems.
But none of this is achievable without early clinician participation across scientific fields to develop new technologies and a deeper understanding of how to harness the body's innate regenerative capabilities. "When I perform a surgical procedure or something is torn or needs to be repaired, I count on the body being involved in regenerating tissue," he says. "So, understanding how the body works to regenerate itself and harnessing that ability is an important factor for the regeneration process."
The Birth of the Vision
Laurencin's passion for regeneration began when he was a sports medicine fellow at Cornell University Medical Center in the early 1990s. There he saw a significant number of injuries to the anterior cruciate ligament (ACL), the major ligament that stabilizes the knee. He believed he could develop a better way to address those injuries using biomaterials to regenerate the ligament. He sketched out a preliminary drawing on a napkin one night over dinner. He has spent the next 30 years regenerating tissues, including the patented L-C ligament.
As chair of Orthopaedic Surgery at the University of Virginia during the peak of the wars in Iraq and Afghanistan, Laurencin treated military personnel who survived because of improved helmets, body armor and battlefield medicine but were left with more devastating injuries, including traumatic brain injuries and limb loss.
"I was so honored to care for them and I so admired their steadfast courage that I became determined to do something big for them," says Laurencin.
When he tells people about his plans to regrow a limb, he gets a lot of eye rolls, which he finds amusing but not discouraging. Growing bone cells was relatively new when he was first focused on regenerating bone in 1987 at MIT; in 2007 he was well on his way to regenerating ligaments at UVA when many still doubted that ligaments could even be reconstructed. He and his team have already regenerated torn rotator cuff tendons and ACL ligaments using a nano-textured fabric seeded with stem cells.
Even as a finalist for the $4 million NIH Pioneer Award for high-risk/high-reward research, he faced a skeptical scientific audience in 2014. "They said, 'Well what do you plan to do?' I said 'I plan to regenerate a whole limb in people.' There was a lot of incredulousness. They stared at me and asked a lot of questions. About three days later, I received probably the best score I've ever gotten on an NIH grant."
In the Thick of the Science
Humans are born with regenerative abilities--two-year-olds have regrown fingertips--but lose that ability with age. Salamanders are the only vertebrates that can regenerate lost body parts as adults; axolotl, the rare Mexican salamander, can grow extra limbs.
The axolotl is important as a model organism because it is a four-footed vertebrate with a similar body plan to humans. Mapping the axolotl genome in 2018 enhanced scientists' genetic understanding of their evolution, development, and regeneration. Being easy to breed in captivity allowed the HEAL team to closely study these amphibians and discover a new cell type they believe may shed light on how to mimic the process in humans.
"Whenever limb regeneration takes place in the salamander, there is a huge amount of something called heparan sulfate around that area," explains Laurencin. "We thought, 'What if this heparan sulfate is the key ingredient to allowing regeneration to take place?' We found these groups of cells that were interspersed in tissues during the time of regeneration that seemed to have connections to each other that expressed this heparan sulfate."
Called GRID (Groups that are Regenerative, Interspersed and Dendritic), these cells were also recently discovered in mice. While GRID cells don't regenerate as well in mice as in salamanders, finding them in mammals was significant.
"If they're found in mice. we might be able to find these in humans in some form," Laurencin says. "We think maybe it will help us figure out regeneration or we can create cells that mimic what grid cells do and create an artificial grid cell."
What Comes Next?
Laurencin and his team have individually engineered and made every single tissue in the lower limb, including bone, cartilage, ligament, skin, nerve, blood vessels. Regenerating joints and joint tissue is the next big mile marker, which Laurencin sees as essential to regenerating a limb that functions and performs in the way he envisions.
"Using stem cells and amnion tissue, we can regenerate joints that are damaged, and have severe arthritis," he says. "We're making progress on all fronts, and making discoveries we believe are going to be helping people along the way."
That focus and advancement is vital to Ennis. After laboring over the decision to have her leg amputated below the knee, she contracted MRSA two weeks post-surgery. In less than a month, she went from a below-the-knee-amputee to a through-the-knee amputee to an above-the-knee amputee.
"A below-the-knee amputation is night-and-day from above-the-knee," she said. "You have to relearn everything. You're basically a toddler."
Kirstie Ennis pictured in July 2020.
Photo Credit: Ennis' Instagram
The clock is ticking on the timeline Laurencin set for himself. Nine years might seem like forever if you're doing time but it might appear fleeting when you're trying to create something that's never been done before. But Laurencin isn't worried. He's convinced time is on his side.
"Every week, I receive an email or a call from someone, maybe a mother whose child has lost a finger or I'm in communication with a disabled American veteran who wants to know how the progress is going. That energizes me to continue to work hard to try to create these sorts of solutions because we're talking about people and their lives."
He devotes about 60 hours a week to the project and the roughly 100 students, faculty and staff who make up the HEAL team at the Convergence Institute seem acutely aware of what's at stake and appear equally dedicated.
"We're in the thick of the science in terms of making this happen," says Laurencin. "We've moved from making the impossible possible to making the possible a reality. That's what science is all about."