There can be various technical difficulties in producing designer babies. Thousands of genetic variations can influence complex traits, psychiatric risk, personality traits, and capacities such as human intelligence. Take any given genetic variant. None has more than a fraction of a single percentage point of an effect on the risk for a psychiatric disorder or condition.
Each of the variants in our genes can have enhancing or diminishing effects on other genes depending on the context in which they are inherited. Genetic variants may be deleterious in some cell types, such as neurons, but advantageous in other cell types, such as immune cells. A lot of scientific evidence shows that chronic stress and poverty contribute to alterations in brain circuitry and blood pressure, dramatically influencing health and mortality.
A gene often has three or four different functions, so altering a single gene may have three or four effects. A gene that builds a protein named “protein S” is a blood coagulant, but it was recently shown to have a critical role in regulation of the immune system. The opposite is also true: multiple biological codes or parts can perform the same function. To engineer new systems would require a complete analysis of an entire network, not just a single gene.
For argument’s sake, let us assume that all these difficulties will be overcome. And we are not talking of the distant future. The time frames being talked about are 15-20 years. If so, what sorts of ethical issues will humanity have to face? In The Code Breaker, Walter Isaacson discusses some thought experiments, which give a flavor of the kinds of questions that we may have to grapple with.
Sharon Duchesneau and Candy McCullough wanted a sperm donor so they could conceive a kid. That sounds straightforward until you are told that both of them are deaf and lesbians and they wanted a child who is also deaf. They consider their deafness to be part of who they are rather than something to be cured, and they wanted a child who would be part of their cultural identity. So they advertised for a sperm donor who was congenitally deaf. They found one, and now they have a deaf child.
Some people condemned them for making a child disabled intentionally but the deaf community appreciated their action. Where do you stand on this? Should they be praised for preserving a subculture that contributes to the diversity? Would it have been ok if, instead of using a deaf sperm donor, the couple had used pre-implantation diagnosis to select an embryo that had the genetic mutation for deafness? What if they had safely destroyed the child’s eardrums after birth?
Now let us look at gene editing that is done to enhance the traits of our children. The MSTN gene produces a protein that reduces muscle growth when they reach a normal level. Suppress the gene and muscle growth is in overdrive. This has already been done to produce “mighty mice" and cattle with “double muscling". Pushy parents and athletic directors who want champion athletes would be very interested. By performing germline editing, they might produce athletes with bigger bones and stronger muscles.
When athletes cheat by using steroids, we find it easy to say that they should be banned. But what do we do if athletes' prowess comes from genes they were born with? For example, almost every champion runner has what is known as the R allele of the ACTN3 gene. It produces a protein that builds fast-twitch muscle fibers, and it is also associated with improving strength and recovery from muscle injury.
Someday it may be possible to edit this variation of the ACTN3 gene into the DNA of your kids. Would that be unfair? Does it matter if those genes were paid for by their parents rather than bestowed by a random natural lottery? In future, would we end up admiring the wizardry of the genetic engineers of athletes rather than the diligence of the athletes?
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