Most parents do their best to protect their children from all kinds of harm. This starts with prenatal vitamins taken by mothers during pregnancy and extends to immunizing children against various diseases and risks. Most of us have good reasons to doubt mothers who abuse control drugs during pregnancy or parents who choose not to vaccinate their children. After all, protecting their children from harm is one of the most important responsibilities of parents.
However, in todays United States, as many as 2% of babies are born with rare genetic diseases caused by a single gene mutation. Sickle cell disease, Tay-Sachs disease and Huntingtons disease are well-known examples of these diseases. What is even more striking is that the number of diseases on this list is thousands. Many babies born with these diseases suffer greatly. Many babies die early. Almost all babies fight the disease for most of their lives.
However, more and more of these single-gene mutation diseases and chromosomal diseases such as Down syndrome are being confirmed by non-invasive prenatal examinations performed by pregnant women at the end of the first three months of pregnancy. Most women around the world know that children with such diseases may face difficulties after birth, so they often choose to terminate pregnancy after making diagnosis. Whatever the reason, and no matter what people think about abortion, these decisions themselves are quite harrowing.
Today, however, a few mothers-to-be get more information about their future children before they become pregnant. By undergoing in vitro fertilization (IVF) and preimplantation genetic testing (PGT), these women were able to know which of the eggs removed surgically from their bodies and fertilized with the sperm of their partner or donor carries a dangerous mutation. In vitro embryos with these diseases will not eventually be implanted into the womb of the expectant mother.
It is absurd to assert that people with fatal diseases should not have more rights to grow up. However, if parents can choose, they will certainly not choose to implant embryos carrying the disease. If future parents have chosen not to implant certain embryos based on our preliminary knowledge of disease risk, what happens when the information on which the embryo selection is based far exceeds thousands of single-gene mutation diseases?
When the first human genome sequencing was completed in 2003, the race to uncover the mysteries of human genetics was just beginning. Although we know little about genetics relative to the complexity of the genome, the progress made on the basis of a deeper understanding is astonishing. Today, doctors can fairly accurately predict single-gene mutation diseases and relatively simple genetic characteristics based on genetic data alone, and the number is increasing.
In the near future, the list will grow to include complex diseases and disease tendencies, percentage probabilities of longevity and healthy life, and more and more complex genetic components of human attributes, such as height, IQ and personality. This predictive power of genetic analysis will flow directly into our fertility clinics, where future parents will focus more on genetic components that will help their childrens future lives, health and abilities when choosing embryos.
Our understanding of genes extracted from early preimplanted embryos suggests that this is only one of the rocket boosters that propel assisted reproduction forward. The second rocket booster will be the ability to induce adult cells, such as skin cells and nucleated blood cells to form stem cells, then transform these stem cells into egg progenitor cells, and finally turn them into egg cells. This will not only eliminate the trouble and risk of hormone therapy and surgical extraction of human eggs, but also make it easier and cheaper to extract an unlimited number of eggs from women.
During IVF, an average of about 15 eggs are extracted from each woman. But imagine how the production of 1,000 eggs would affect a range of possibilities for preimplantation embryo selection. Each of these 1,000 eggs is a natural offspring of both parents, but the difference between them will make it possible to select eggs with the strongest genetic expression of a particular trait, such as those with the highest genetic IQ potential.
The third rocket booster will use gene editing techniques, such as CRISPR, to edit the genomes of preimplantation embryos or sperm and eggs used to make embryos. Just this week, Chinese researchers announced that they had used CRISPR to edit the CCR5 gene in a pair of preimplantation twins to immunize them against HIV. This is the first time that human beings have been genetically edited, and it is also a harbinger of the coming era of genetic engineering.
The amazing complexity of the human genome will limit our ability to safely make too many simultaneous genetic changes in human embryos, but over time, as our knowledge and technological capabilities improve, our ability and willingness to make these types of changes for future children will increase. With so many risks, future parents will increasingly face tough choices when deciding how to conceive their children.
If they stick to the traditional way of sex, they will experience the kindness and wisdom of nature and the unpredictable cruelty. If they adopt IVF technology and become more knowledgeable about embryo selection, they will eliminate most single gene mutation diseases and possibly improve their childrens chances of living longer and healthier lives, and have more chances than their unreinforced peers. However, if these children do not particularly like the way they are optimized, or think they are some kind of weird consumer product with emotions, then parents will also put their children in pain.
Although traditional sex and IVF have their own advantages and disadvantages, traditional sexual conception may have fewer advantages than laboratory conception. Differences and competition within and between societies will force parents and societies to adopt more active forms of reproductive technology, provided they believe that doing so will open up more possibilities and create opportunities for the next generation, rather than closing them down.
Pregnancy through sex will be as useful as ever, but laboratory pregnancy will only become more popular. Over time, only fanatics will choose to risk their future childrens health and well-being, rather than investing in protecting their children from harm and helping them optimize their future life potential, as parents have always done. Although sexual conception is increasingly seen as similar to not vaccinating children, it is still a completely natural selection process today, bringing huge potential risks and costs to yourself, your children and your community.
However, as the future of genetically engineered babies gets closer and closer, the revolution in genetics and assisted reproductive technology will raise enormous, thorny and significant questions about how we value and invest in diversity, equality and our own basic human nature, and we are not ready to deal with them at all. But these revolutions came sooner than most of us understood or prepared, so we had better be ready now. Because the ultimate direction of this path goes far beyond sex, and as a fundamental change in the evolution of our species, it should concern each of us. (small)
Source: Liable Editor of Netease Science and Technology Report: Yao Liwei_NT6056