The World Anti-Doping Agency’s fundamental purpose is preserving “the spirit of sport.” In its official Code, WADA describes that spirit as “the essence of Olympism, the pursuit of human excellence through the dedicated perfection of each person’s natural talents.”
One case study in understanding how genetics can shape our aptitude for sport is height. Basketball coaches say you can’t teach height. That’s certainly true, and being taller is a major advantage in that sport. Within a population, tall parents tend to have tall children and short parents tend to have short children.
But good nutrition and health also matter a great deal. The average height of 18-year-old South Korean women increased nearly eight inches between 1914 and 2014. Their genes didn’t change; their diets and overall health improved. Indeed, the average height of a population is a useful index of its overall health and diet.
Scientists have identified roughly 700 genes working together to affect height, mostly in tiny increments. A recent study, however, reports 24 rare variants that make at least a one-centimeter difference in adult height. (There are 2.54 centimeters in an inch. It’s worth noting that some variants result in being shorter, not taller.)
Now imagine someone trying to increase height by inserting one of the rare height-increasing genes. It would be futile in a mature adult. The growth plates at the end of our bones fuse in our teens—in girls a couple of years earlier than in boys. It would have to be a human being at a very early stage of development, an embryo perhaps.
What gene editing might mean for athletes
Or perhaps they might use the CRISPR-Cas gene editing technique employed in a handful of recent studies with human embryos and gametes. CRISPR utilizes a defense created by bacteria that “memorizes” bits of DNA sequence from invading viruses. When it detects a similar stretch of DNA it uses a protease—an enzyme that cuts DNA—to disable the virus.
Last summer researchers reported using CRISPR to “correct” a gene known to cause hypertrophic cardiomyopathy, the most common cause of sudden death in healthy young athletes. But instead of editing the genome of embryos, they targeted gametes—sperm and eggs. The mutation is dominant meaning that inheriting a single copy results in the condition. Without gene editing, half of the resulting embryos would be expected to inherit the disease. Instead, of the 58 embryos created after CRISPR, 42 did not have the mutation rather than the 29 expected.
In theory, CRISPR could be used to try to insert into gametes a gene or genes linked to a trait, such as height or strength, thought to be advantageous in sport. PGD--Pre-implantation genetic diagnosis most commonly takes place with a 3-day old embryo.The resulting embryos might then be examined via PGD to identify the ones that incorporated the desired genes, which could then be selected for implantation. The result? Children with genomes edited for optimum sports-related talents.
What could possibly go wrong? What could possibly be wrong?
Lots can go wrong. CRISPR-Cas gene editing can miss its target, disrupting other genes essential for a healthy life. If used on embryos it may edit the genes in some but not all cells resulting in a patchwork of edited and unedited cells that scientists call a “mosaic.” If the edits don’t make it into the crucial tissues and organs you won’t get the desired impact. We’d also need to be able to detect abnormalities caused by missed targets and editing errors.
Then there’s the problem of many genes interacting in complex, poorly understood ways to contribute to whatever “natural” talents we may have. Few genes have been linked to elite athletic performance; so far, none can be used to predict athletic success. Choosing the “right” gene to edit won’t be easy. Complicating matters further, many genes have multiple effects. So successfully editing that “height” gene could also affect other traits in ways you’ll regret.
So what's considered 'natural'?
Beyond the worries about the science of gene editing, yellow and red lights are flashing violently with ethical warnings. In February, the National Academy of Sciences and the National Academy of Medicine in their report on human gene editing urged that clinical research trials on inheritable alterations be permitted “only for compelling purposes of treating or preventing serious disease or disabilities, and only if there is a stringent oversight system able to limit uses to specified criteria.” Regarding gene editing for enhancement, they said: “Do not proceed at this time with human genome editing for purposes other than treatment or prevention of disease and disability.”
The notion, then, that we could enhance someone’s “natural” talents by tinkering with their genes just before or just after fertilization is fraught with both practical and moral difficulties. Which gene(s) should we target? Can we be confident of the intended result many years later? Are the risks to a child outweighed by whatever competitive advantage in sport might result?
There’s a second, equally significant ethical dimension here. It’s true that parents can and should have expectations for their children. That they grow to be good, generous, hard working adults; that whatever talents they have, in sport, music, with their hands or their minds, be nurtured; that they be happy and that their presence in others’ lives be a blessing. But excessively narrow expectations can be oppressive. Perhaps your daughter is exceptionally bright but loves above all to work with her hands. Perhaps your son is artistically gifted but really, really, wants to teach high school science. Imagine that you’ve invested in gene editing to install athletic talents in your child. What if that girl or boy isn’t as talented as you’d hoped? Or simply doesn’t want to pursue sport? At what point does trying to do what’s best for your child mutate into overweening parental control?
Imagine for a moment that all the scientific and ethical problems went away. Should we think of athletic talents resulting from gene editing as “natural” in the way the WADA Code, and most people, typically do? Sport has already banned gene doping of adult athletes. But should we think of a child born with an edited genome in the same way? That child certainly had no choice. But neither did the young East German girls systematically doped by their government who went on to dominate Olympic swimming for years.
The concept of the “natural” turns out to be imperfect, contestable, but also necessary and useful. In bioethics, the concept of “death” continues to be debated. We don’t have a universally accepted definition after decades of fierce debate; but the hard-won compromises we’ve forged are solid enough for rules that allow us to retrieve organs and transplant organs that save lives. When we emphasize something’s “naturalness” we’re pointing to a source of its value. It’s the difference between the grandeur of the Grand Canyon and the manicured prettiness of Disneyland. Both may be worth preserving—but for very different reasons.
Human-installed talent does not necessarily qualify as “natural.” That doesn’t make the child any less worthy of respect. But it does mean that sport has a legitimate interest in discouraging that particular and peculiar form of enhancement.