How sex ed has changed.
In the future, perhaps as early as 2045, will most planned pregnancies be conceived in the in vitro fertilization (IVF) lab; the eggs, sperm and embryos comprehensively screened for genetic disease-associated mutations, ranked and scored for probabilities of more poorly-defined traits, and subjected to all sorts of genetic modifications? Will parents of the future face something between an opportunity and an obligation to dial in and dial out the traits that define their (or their insurance company’s) vision of a perfect baby: minimizing disease risks, maximizing talents and desired physical attributes and abilities, and when necessary trading one predisposition for another?
Will the benefits of these interventions be so compelling that those who choose to conceive in vivo (aka the old fashioned way) will be shunned as mid twenty-first century Luddites, carelessly leaving the important process of evolution to natural selection? For those with access to the technology, will this proactive genetic intervention mean the end of disease, a democratization of innate talents, …and the ubiquity of broad shoulders, thin waists and great hair?
And will this be the end of sex?
Welcome to Hacking Darwin, Jamie Metzl’s timely, important, and thorough exploration of how inheritance will evolve from natural selection to a human-controlled generation-by-generation data hack. And while some of the scenarios for the future of human reproduction that he describes may seem far-fetched, they effectively illustrate the power of the reproductive technologies being developed, and the challenge of using them responsibly.
Hacking Darwin has two parts, a Darwin (historical) part and a Hacking (futuristic) part. The first is a meticulously researched and written history of reproductive genetics, from Mendel and Darwin to Watson, Crick and Franklin, to Steptoe and Edwards, along parallel paths of basic science, medicine and bioethics. Anyone seeking perspective and background for the coming debates on gene modification, de novo egg and sperm creation, and the movement towards consensus on preimplantation genetic diagnosis for miscarriage and genetic disease prevention, fertility preservation in cancer survivors, reproductive alternatives for the LGBT population and proactive family planning using vitrification of eggs and sperm should start here.
The second part of the book, running alongside and interspersed with the first, is a science/science fiction hybrid that tells the “where all this could be heading” story, and includes a future where our babies are chosen from a menu, one trait after another, where we extrapolate from the precision that preimplantation genetic diagnosis techniques offer for single gene mutation disease (sickle cell anemia or thalassemia, for example) prevention today, relatively low hanging fruit bioscience-wise, to seemingly anything that occurs in the nuclei of human eggs, sperm and embryos.
Read these sections carefully, and skeptically. The connection between what we can do in the one gene, one disease at a time present does not necessarily translate into a many genes, many diseases plus talents/physical traits future. And development of the science does inevitably lead to mass acceptance and adoption by patients/consumers. (The one place where the presentation falls flat is the brief visits to a fertility clinic of the future, where a clinician of some sort describes the new procedures to a patient. One of author’s few under-developed talents is dialogue; I would not wait in line for tickets to his first play).
If Hacking Darwin is less successful projecting the arc of progress into the future than it is in tracing the past’s path to now, that’s because we have graduated to much more complicated problems, from precision medicine to “I know them when I see them” disorders like autism or Alzheimer’s disease, and traits and predispositions like intelligence or empathy. We are all the sum total of many relative deficiencies, strengths and weaknesses, each with a more or less detailed genetic signature. The genetic decisions of the future will not be good gene / bad gene binaries; biology has decades and perhaps centuries of humbling lessons in store for us.
Further, one can (and should) argue that any 2019 survey of reproductive genetics will overstate the connection between DNA and disease (or DNA and destiny) and place too little emphasis on the post DNA dynamics: the regulation of transcription and translation and how different environmental, microbiomic, metablomic, proteomic, and -omics to be named later. We should approach calculating polygenic risk (and, more importantly, acting on these calculations) with caution. Applying (and therefore implying) digital precision to analog definitions of disease (or talents) is a good way to do the wrong thing for the right reasons.
A final argument against predictions of an explosive adaption of complex and comprehensive proactive genetic intervention: we have really effective versions of it available now, and hardly anyone uses them. We have been able to identify single gene mutations in embryos during IVF in order to prevent establishing an effected pregnancy for over two decades. If this 100% severe childhood disease prevention has not moved the needle, why do we think that changing percentage risk for chronic or adult illnesses will? Maybe this will take time, maybe we need to reach more than the 30,000 families who deliver children with genetic disease in the United States each year. Certainly cost and access is another factor, inadequate patient (and doctor) knowledge of the procedures is another. But will this dynamic change with time and more advances in the technology?
There is so much to like about Hacking Darwin. The author speaks many languages: genetics, data science, eastern and western politics and philosophy and how they affect medical and scientific innovation, and the history and sociology of science. His humble, academic treatment of biology’s recent past provides a perspective and grounding that makes the more implausible scenarios for the future seem possible and reasonable, but not necessarily inevitable. Eventually these arcs of history, discovery and science will make everything in Hacking Darwin realistic, and some of it real.
It’s time to clear a section on the bookshelf for a future of reproduction section. In addition to Hacking Darwin, I would highly recommend Carl Zimmer’s She Has Her Mother’s Laugh and Hank Greely’s The End of Sex and the Future of Human Reproduction, together an excellent start to a syllabus for the new sex ed.