Genome Editing

Angelica Cheng

Active Member

Permitting IVF polygenic testing is a slippery slope to genome editing in hyper-competitive Asian societies like Singapore

The Asia-Pacific region has seen rapid economic growth over the past few decades, fueled in large part by hyper-competitive social norms and Confucian values of various East Asian societies that emphasize hard work, frugality and education. The phenomenon of “tiger parenting” is common and widespread in these Asian societies, with many parents competing to get their children into the best schools even before they are born, through expensive purchases of residential properties near prestigious elementary schools.
Nowhere is this more apparent than in Singapore, which has a prevalent “kiasu” (afraid to lose) mentality in society. In this small ultra-rich city state, parents often push their children into the educational rat race at a very young age, and typically spend a large proportion of their income on after-school tuition fees. The absurdity of “tiger parenting” has even extended to recreational and enrichment activities such as music, sports, and art, whereby parents try their best to get their children to participate in various competitions, to inculcate the principle of trying to excel in everything they do.
Nevertheless, the major confounding factor to any parent’s best-laid plans is the randomness and unpredictability of the natural process of fertilization that involves mixing and recombining genes from the sperm and egg to produce new genetic variants. This is often manifested by siblings born from the same set of parents differing so much in looks, health and academic ability. Hence, there is always the worrying possibility that a child born of high-achieving parents may not necessarily be a high-achiever; with the risk that all the effort and money invested in a “dud” child will completely go to waste.
The advent of polygenic scoring in preimplantation genetic testing (PGT-P) of IVF embryos could possibly provide a solution to this confounding challenge. These can be applied both for the prevention of genetic diseases, as well as enhancement of socially-desirable traits such as intelligence, athletic ability and beauty standards linked to tallness, fair complexion, hair and eye colour.
Polygenic testing refers to evaluating an individual embryo’s likelihood of developing an adult-onset, multi-factorial trait by analyzing the combination of specific genetic variants within its genome.
For example, type II diabetes, obesity, intelligence, height, and skin complexion are such complex traits determined by the combination of multiple genes, so polygenic scores based on the presence of multiple gene variants are used to estimate the likelihood of developing such traits later in life. Currently, artificial intelligence (AI) algorithms are specifically being developed for such complex screening and analytical processes in polygenic testing. In a recent medical breakthrough, researchers in China used polygenic testing to select IVF embryos with less risks of developing family-related diabetes, for parents with a family history of the disease.
Unlike serious safety issues with human genome editing, there are minimal risks involved in polygenic testing and selection of IVF embryos, because there are no permanent man-made genetic modifications that would be passed down to future generations. It is basically a technique for picking the “winning ticket” in the “genetic lottery” of fertilization for good health, intelligence and other socially-desirable traits. Hence, this technique thus represents an attempt to overcome the unpredictability and randomness of the natural process of human fertilization to yield the best outcome.
This is a particularly lucrative business opportunity for fertility clinics, because parents naturally and instinctively want the best for their children, particularly in a hyper-competitive Asian society like Singapore. Indeed, a recent large-scale survey conducted in the US showed that 38% of respondents indicated that they would use polygenic testing to improve their child’s IQ and academic performance, to better their chances of entering an elite college. The corresponding figure would likely be much higher in Singapore.
Very likely, Singapore would ban polygenic testing of IVF embryos for selection of non-disease traits such as intelligence, while allowing its use for prevention of complex multi-factorial diseases such as type 2 diabetes.
However, this could possibly lead to a “slippery slope” situation, whereby the need to prevent common family-related disease traits such as type 2 diabetes can be readily exploited as a “convenient excuse” to also secretly select for non-disease socially-desirable traits such as intelligence, tallness and fair complexion.
The fact remains that the genomic DNA sequence of IVF embryos will likely be made available to patients who did polygenic testing for preventing diseases such as type 2 diabetes. It is difficult to deny such data to patients who pay for it, particularly for private DNA sequencing companies with overseas branches or headquarters. With just a few clicks, encrypted digital data anonymously labeled with QR or bar codes can be secretly transferred across the globe. These patients can first freeze their DNA-sequenced IVF embryos, and send such data overseas for prediction of intelligence, tallness and fair complexion, without any involvement of the fertility clinic or knowledge of their doctor.
Additionally, it is foreseen that the technical limitations of IVF polygenic testing would very soon lead to much disappointment and frustration among its many eager proponents, who expect to see vast improvements in their offspring after spending so much money.
For example, the statistical probability of two short parents conceiving a tall child by polygenic testing would always remain low, because most of the genes that predispose to tallness are simply absent in those parents. The same can be said of two average IQ parents attempting to conceive a high IQ child, or two dark-skinned parents attempting to have a fair-skinned baby by polygenic testing. In fact, because most selections occur between embryos with the same parents, this substantially limits genetic variability, and hence limits the usefulness of polygenic testing in targeting complex traits such as intelligence, tallness and fair skin. There is a much reduced number of possible outcomes, when selecting for specific characteristics within such a small sample size with limited variability, which obviates the usefulness of any selection method.
This would likely result in the disappointed and frustrated customers of IVF polygenic testing advocating for a better and more effective method to conceive their perfect “dream child”. That would most likely be human genome editing with all its risks and safety issues.
An appropriate analogy here would be a drug addict progressing from soft drugs such as cannabis, to hard drugs such as heroin and crack cocaine, because of temptation to be gratified by better and longer-lasting “highs”. Hence, permitting IVF polygenic testing would likely be a slippery slope to human genome editing in a hyper-competitive Asian society like Singapore.
 

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Should Singapore permit genome editing of human embryos?

A major biomedical breakthrough won the 2020 Nobel Prize for CRISPR technology for genome editing, which can potentially save the lives of many people afflicted with genetic diseases.

Currently, there is an international consensus that the use (or abuse) of genome editing for human enhancement is unethical. It is unethical to use genetic engineering to seek desirable traits in intellectual or athletic prowess, or physical characteristics such as skin color and height.

However, genome editing of somatic (non-reproductive) cells for curing genetic diseases is widely considered to be acceptable. And, currently, some clinical trials are going on in this area.

What has not yet been resolved are ethical issues in genome editing of human embryos and reproductive (germline) cells for preventing genetic diseases. This is best exemplified by the infamous case of the Chinese scientist He Jiankui, who was sentenced to prison for carrying out genome editing of human embryos to confer HIV resistance.

Such controversy would certainly be of interest to the ultra-rich and technologically-savvy city-state of Singapore, which has invested heavily in biomedical research in recent years, and developed a comprehensive system of biomedical regulations and ethical review.

There are some ethical and moral issues that Singapore has to resolve in deciding whether or not to permit genome editing of human embryos in IVF treatment.

No life-saving effort

As genome editing of human IVF embryos is not life-saving in itself but intended to save the life or health of a yet unborn future offspring, there is much less necessity and urgency as compared to curing patients who are suffering from life-threatening genetic diseases.

The key objective in this should be to enable patients with known genetic defects to have healthy genetically-related offspring of their own, rather than adopting a baby or resorting to egg donation.

This is in line with legal precedents in Singapore which stresses people’s desire to have children that carry their genes as a basic human impulse. It also aligns with the predominantly Confucian sociocultural values of Singapore that emphasize lineage continuity within traditional family formation.

Another major issue of contention is the availability of much safer and less complex options for preventing the transmission of known genetic defects to future offspring, in particular Preimplantation Genetic Testing (PGT) of human embryos. It raises a question: If PGT is a readily available option, why use genome editing?

The PGT is a mature technology platform with proven effectiveness in screening and weeding out various known genetic defects in IVF embryos. Compared to genome editing of human embryos, PGT is much safer as there are no permanent genetic modifications that can be transmitted to future generations. It is basically a technique for screening IVF embryos for inheritance of specific known genetic defects.

Nevertheless, there may be some cases whereby genome editing could be preferable to PGT. For example, the very few healthy IVF embryos typically produced by older women would only provide a small sample pool. This may not give much choice in the selection for non-inheritance of known genetic defects, so it may be worthwhile taking the risks with genome editing.

Moreover, older women tend to produce weaker lower-quality embryos that could make them more vulnerable to damage by cell extraction (biopsy) for genetic testing. Other cases may include rare instances whereby both parents are afflicted with the same genetic disease, particularly those involving dominant rather than recessive gene mutations, such as neurofibromatosis.

Yet another alternative would be to carry out gene therapy on the fetus while still in the womb. Upon prenatal diagnosis of genetic diseases, cells can be extracted from the fetus with advanced surgical techniques, subjected to genome editing, and re-transplanted back to the fetus. This is more easily achieved because millions of cells are available in the fetus, unlike the few cells of an embryo.

Redundancy of genome editing

Due to variable permutations in the recombination of different genes during the fertilization process, some embryos may inherit the known genetic defects of their parents, while other embryos may be healthy. Indiscriminate genome editing done on the entire batch of IVF embryos before ascertaining which of these carry known genetic defects by genetic testing (PGT) may unnecessarily expose healthy embryos to redundant genome editing, which could result in detrimental effects.

Here lies the contradiction. If initial genetic testing is required to screen genetic abnormalities in IVF embryos before genome editing; what then is the use of genome editing? Genome editing becomes redundant because some healthy embryos have already been identified during the screening process. Even in rare instances where all embryos are found to be genetically abnormal, the patient can simply attempt another round of IVF.

Cost-benefit rationalization

The occurrence of genetic diseases is relatively rare and even much rarer are instances whereby genome editing could be more advantageous than PGT in preventing transmission of genetic diseases.

The extremely small market size would question the commercial viability of genome editing of human embryos in IVF treatment, as well as its ability to boost Singapore's low fertility rate.

Safety issues in genome editing

Genome editing with CRISPR technology is neither completely error-free nor without potential risks. These include unintended on-target and off-target gene editing errors, and insufficient editing resulting in mosaicism, whereby only some but not all cells within the embryo have the correctly-edited genes.

The relatively small numbers of embryos typically produced by each couple during IVF treatment would thus impose severe limitations in screening out such gene-editing errors due to the extremely small sample size. By contrast, millions of non-reproductive (somatic) cells are readily available for genome editing and subsequent screening of gene-editing errors.

Furthermore, current knowledge of the complex interactions of genes involved in genetic diseases is still very limited, and there is always the risk that the detrimental side effects of genome editing may manifest much later in adult life.

More recently, a new study reported that CRISPR gene editing on human embryos may have dangerous consequences; because the cells of early human embryos often cannot repair DNA damage caused by the genome editing process, unlike other non-reproductive (somatic) cells of the human body.

Considering the various controversial issues and drawbacks associated with genome editing of human embryos for preventing genetic diseases, coupled with the extremely small market size and limited commercial viability, it may not be worthwhile for Singapore to invest and develop genome editing of human embryos in IVF treatment.

It is speculated that the only commercially viable and lucrative market for genome editing of human embryos could lie in its application for human enhancement rather than disease prevention. This is however unlikely to be permitted in Singapore, given current government policy that biomedical regulation in the country must conform to international consensus and standards.
 
https://bioedge.org/enhancement/should-singapore-embrace-human-enhancement/

Should Singapore embrace human enhancement via germline genome editing?

Recent years have witnessed the emergence of a “New Eugenics” movement by highly-educated technopreneurs and white-collar professionals in Western countries, who believe that it is their natural right (based on individual reproductive autonomy) to screen, select or genetically engineer non disease-related socially-desirable traits in their offspring, such as high IQ, athletic prowess and physical beauty traits such as height, skin complexion, eye and hair colour.

The advent of the Nobel prize-winning CRISPR-Cas9 technology thus provides such opportunities for human genetic enhancement.

The “new eugenics” and a close cousin “pronatalism” are predominantly rooted in Western secular liberalism with little or no religious overtones, based on the concept of “procreative beneficence”. This holds that parents have significant moral reasons to select, of the possible children they could have, the child who is most likely to experience the greatest well-being – that is, the most advantaged child, the child with the best chance at having the best life.

Many new eugenicists believe that they are being socially responsible by not only committing to reproduce prolifically to compensate for declining birthrates in their respective countries, but also by enabling the world to be increasingly populated by their “genetically superior” offspring, who will lead longer, healthier, better and more fulfilling lives, and contribute more to the advancement of human civilization through their superior intellect.

Nevertheless, instead of altruism and civic consciousness, this appears to smack more of egoism and narcissism in the misguided belief of the superiority of their own upper middle-class family values and genetic heritage.

One prominent proponent of pro-natalism is the billionaire Elon Musk. He currently has 11 children by three different women, most of whom were artificially conceived by IVF. After the birth of one of his many children, he had previously tweeted “Doing my best to help the underpopulation crisis. Population collapse due to low birth rates is a much bigger risk to civilization than global warming.”

There is a very real danger that such misguided ideals could find traction and take root in East Asian Confucian societies such as Singapore, which by their very nature are hyper-competitive and obsessed with material success, social status and academic excellence.

Disabled people with physical or intellectual handicaps are heavily stigmatized in these societies and are often scorned as a burden to society and as a shame and embarrassment.

Moreover the demographic transition of East Asian Confucian societies to ultra-low fertility rates, with most families having only one child due to high living costs and educational stress, may in turn motivate prospective parents to utilize new assisted reproductive technologies to beget children with the “best” or “most optimal” genetics, rather than leaving it to chance via the natural fertilization process that involves the mixing and recombination of genes in a random manner.

Indeed, indigenous eugenics movements have also sprung up in East Asian Confucian societies. Take, for instance, the “uterine morality” (zigong daode) movement in mainland China amongst feminists, which argues that because women bear the brunt of birthing and caring for children, they should only accept only the very best genetic material into their wombs. In essence, for a woman to have good “uterine morals”, she must take responsibility for her future children by selecting a good-looking, intelligent, strong, financially-sound man with no family history of genetic disorders, so as to ensure that future generations evolve into healthy, beautiful, and intelligent beings.

One drawback to this is that realistically, there are simply not enough of such “good men” to go around. A recent book published by Yale professor Marcia Inhorn pointed out that increasing numbers of educated women worldwide are freezing their eggs because there are simply not enough suitable men that can match them in terms of education and income levels, as women tend to graduate from universities at higher rates than men.
 
Nevertheless, if Singapore were to subscribe to these narratives, and permit the application of germline genome editing for human enhancement, it must beware of the following consequences:

  • Damage to Singapore’s reputation as an international hub for biomedical research and industry, if this contravenes global consensus and widely accepted ethical norms. Public sentiment worldwide is overwhelmingly against germline gene editing for human enhancement.
  • Unnecessary use of expensive, invasive and risky assisted reproduction techniques by fertile and healthy couples, just to avail themselves of the opportunity to genetically modify their offspring for amplifying non-disease related socially desirable traits, rather than as treatment for infertility or as cure for genetic diseases. This would be tantamount to clinical malpractice by fertility doctors and clinics.
  • Further decline in Singapore’s already low fertility rates by increasing the financial costs of having a child. Germline genome editing for human enhancement will not come cheap. Moreover, there are also additional medical fees for complex assisted reproduction procedures that are required for germline genome editing. If human genetic enhancement becomes a fad in Singapore, many prospective parents desiring two or more children, may eventually decide on having just one superior “genetically enhanced” child due to the high costs involved.
  • Increased social inequality and tensions between rich and poor. Only the rich can afford to use such expensive techniques on their offspring. This could in turn lead to further amplification and exaggeration of socially desirable traits such as high IQ, athletic prowess and physical beauty among the more affluent sections of society.
  • Reinforcement of racial discrimination and social bias against ethnic minorities. Many Asian women use skin-whitening cream, dye their hair blonde and wear contact lenses that make their eye pupils look blue, because they consider these traits to be beautiful and desirable. Why not genetically-engineer these traits into their offspring? Would this not imply that certain races are more beautiful and desirable than others? Such reinforcement of social biases in beauty standards would obviously be inimical to efforts by local policymakers to build a more inclusive and cohesive society.
  • Contrary to the concept of a level playing field in society, analogous to the ban on sports doping. Athletes do not always start out equal nor are they given the same opportunities. Some athletes may be advantaged by their superior physique conferred by genetics, others from richer countries may receive much better training and nutrition compared to those from poorer countries. But yet all major international sporting organizations ban doping, most commonly anabolic steroid use, to ensure a level playing field and same starting point among athletes. Should not Singapore ban human genetic enhancement to ensure a level playing field in society?
  • Disruption of family harmony, due to parents having unrealistic expectations of their genetically modified children after spending so much money. There may also be jealousy and resentment between siblings if only some of them had received genetic enhancement, while other had not.
  • Aim of enhancement does not justify medical risks incurred. Genome editing with CRISPR-Cas9 technology is neither completely error-free nor without potential safety risks. These include unintended on-target and off-target gene editing errors, and insufficient editing resulting in mosaicism, whereby only some but not all cells within the embryo have the correctly edited genes. There have also even been reports of entire chromosomes being unintentionally deleted during gene editing.
  • Trespass and violation of the individual autonomy and rights of the unborn child, who had never consented to being genetically modified in the first place. This is particularly significant if substantial medical risks are incurred during germline genome editing.
  • Unexpected and unintended detrimental effects of germline genome editing may manifest in offspring much later in life, for example certain types of cancer or neurodegenerative disease. We can expect lawsuits against biotech companies, government regulatory agencies and even parents for harms of conception.
What kind of country does Singapore want to become? A more inclusive and cohesive society, or a more competitive “cut-throat” and social status-conscious one?
 

Ethics of germline genome editing to prevent genetic diseases from an Islamic perspective

In 2018, Dr He Jiankui announced he created the world's first genome-edited babies (BioNews 977), which sparked a call for a five-year moratorium on germline genome editing. As this moratorium ends, it is timely to ask how do we progress from here?
As Muslims form a significant fraction of the world's population, understanding Islamic perspectives is crucial for the biomedical industry.
Currently, the overwhelming majority of Islamic scholars agree that genome editing for human enhancement, eg, to amplify traits such as high IQ, athletic prowess, height and complexion is prohibited (haram). This would be tantamount to tampering with God's creation (Taghyir Khalq Allah), as attested by several fatwas (Islamic religious rulings) issued by reputable Islamic organisations.
Nevertheless, germline genome editing to prevent genetic diseases still elicits some degree of controversy among Islamic scholars. Previous debates had mainly focused on safety aspects, informed consent and breaches of biomedical regulations. What have largely been overlooked are comparisons with alternative (possibly better) techniques for preventing or curing genetic diseases, and technical differences between germline versus somatic (non-reproductive) genome editing. Moreover, more recent research points to additional safety flaws of the CRISPR/Cas9 approach (see BioNews 1127). A fresh look is thus warranted.
To resolve conflicting opinions, it is best to critically examine whether this is aligned with Islamic principles based on Qawaid Fiqhiyyah (Islamic legal maxims) that incorporates Qaṣd (intention), Yaqin (certainty), Ḍarar (injury), Ḍarurah (necessity), and Urf (local customs).
This is often used as a roadmap in debates on Islamic bioethics, which usually requires an independent or original interpretation of new issues (Ijtihād) that are not explicitly mentioned by the Quran and Hadiths (prophetic traditions). Rather than providing a definitive answer as permissible (halal) or prohibited (haram), this approach facilitates a thorough examination of the issue at hand through the lens of well-established and universally accepted principles.
The first legal maxim related to Qaṣd (intention), refers to evaluating new medical technologies based on the intended objectives of its applications.
In this case, the key objective is to enable Muslims, who are carriers or affected with a genetic disease, to have healthy blood-related offspring of their own, rather than opting for Muslim-style adoption (Kafala). Resorting to gamete donation is explicitly prohibited by the Sunni branch of Islam, as this is considered akin to adultery (Zina).
This would thus align with one of the five key objectives of sharia law (Maqasid al-Shariah), namely the protection of lineage or progeny (Hifz al-Nasl).
The second legal maxim related to Yaqin (certainty) within the context of Islamic bioethics, refers to the current state of scientific knowledge and effectiveness of new medical techniques, and whether there are any safer or better alternative treatment options.
In this case, there is a much safer and less complex alternative technique – preimplantation genetic testing (PGT) of human embryos, a mature technology platform with proven effectiveness in screening various known genetic defects in IVF embryos, without any risks of permanent genetic modifications being transmitted to future generations.
Nevertheless, there may be some cases whereby genome editing could be preferable to PGT. For example, rare instances whereby both parents are affected with the same genetic disease, particularly those involving dominant rather than recessive gene mutations, such as neurofibromatosis.
It must be noted that due to variable permutations in the recombination of different genes during the fertilisation process, some embryos may inherit the known genetic defects of their parents, while other embryos may be healthy. Therefore, if PGT is required to screen genetic abnormalities in IVF embryos before genome editing; what then is the use of genome editing? It becomes redundant because some healthy embryos have already been identified during the screening process. Even in rare instances where all embryos are found to be genetically abnormal, the patient can simply attempt another round of IVF.
Yet another alternative would be to carry out gene therapy on the fetus in utero. Upon prenatal diagnosis of a genetic disease, cells can be extracted from the fetus with minimally-invasive surgical techniques, subjected to genome editing, and re-transplanted back to the fetus. This is technically easier to achieve because thousands of cells are readily-available from the fetus, unlike the very few cells of an embryo.
The third legal maxim related to Ḍarar (harm) questions the risks of potential harms associated with new medical techniques.
Genome editing using the CRISPR/Cas9 approach is neither completely error-free nor without risks. These include unintended on-target and off-target errors, and mosaicism, whereby only some but not all cells within the embryo have the correctly-edited genes.
The relatively small numbers of embryos typically produced by each couple during IVF treatment would thus impose severe limitations in screening out such gene-editing errors due to the extremely small sample size. By contrast, millions of non-reproductive (somatic) cells are readily available for genome editing and subsequent screening of gene-editing errors.
More recently, cells in early human embryos have been shown to be unable to repair the DNA breaks made during CRISPR/Cas9 genome editing process (see BioNews 1196).
The fourth legal maxim related to Ḍarurah (necessity), questions the necessity and/or urgency of using new medical techniques.
Because germline genome editing of human IVF embryos is not life-saving in itself but intended to save the life or health of a yet unborn future offspring, there is much less necessity and urgency as compared to curing patients who are affected by serious genetic diseases. Hence, it should be ranked lower in priority for public healthcare spending and Government-funded research, based on the Islamic concept of Fiqh al-Awlawiyyat (understanding of priorities).
The fifth legal maxim related to Urf (local customs), refers to taking into account local customs and traditions (if they are compatible with Shariah), when deciding on any new issues, such as novel medical techniques.
In this case, the devastating impact of serious genetic diseases on patients and their families is well-known. Hence there is almost universal public support worldwide for developing new medical techniques to prevent genetic diseases.
The pertinent question is whether germline genome editing is the best solution?
 

3 reasons why S'pore is justified in restricting genetic screening of IVF embryos

I refer to the article "Baby Steps: 'Toughest period of my life', say women who underwent costly, emotional IVF process. Can more be done to support them?" (Feb 13).
It stated that some Singaporean couples travel overseas to do pre-implantation genetic screening (PGS) of their in-vitro fertilisation (IVF) embryos, due to restrictive regulations at home.
Currently, PGS is only open to women who are 35 and above, or those regardless of age who have two or more failed IVF procedures or two or more recurrent pregnancy losses.
In 2020, the Ministry of Health (MOH) said only 104 patients had undergone PGS thus far.
It is necessary to understand the various drawbacks of PGS and why it is so strictly regulated by MOH.
First, patients must be aware that genetic screening can potentially damage their embryo.
The technique is highly invasive, involving drilling a hole through the embryo shell and extracting cells for biopsy. This is potentially harmful and can impair its development.
Experts have pointed out that studies claiming no ill effects of PGS on embryos are often based on testing of excellent high-quality embryos rather than more "delicate" lower-quality embryos that might suffer more.
Because older women tend to have weaker lower-quality embryos, these may be more prone to damage upon testing.
Second, genetic testing is prone to misdiagnosis, which could result in patients discarding viable embryos that can give rise to a healthy baby.
This is because the testing involves extracting cells only from the outer embryo layer that produces the placenta and umbilical cord, which is not representative of the inner embryo layer that gives rise to the baby itself.
"Mosaic embryos" containing a mixture of genetically normal and abnormal cells have demonstrated the ability to self-correct and produce a healthy birth.
This "self-correction" mechanism involves pushing out the genetically abnormal cells into the outer embryo layer, which gives rise to the placenta and umbilical cord.
Older women have a limited number of embryos during IVF.
Therefore, excluding or discarding mosaic embryos that can potentially give rise to a normal baby, would substantially reduce their chances of IVF success. Some older IVF patients may have no embryos left to transfer after genetic testing.
Third, several large-scale clinical studies have shown that PGS does not improve IVF success rates.
In 2019, a large multi-centre randomised clinical trial involving 34 IVF clinics in the United States, Canada, United Kingdom, and Australia and including 661 patients aged between 24 and 40 years, found no significant overall improvement in IVF success rates with PGS.
In 2021, another large clinical trial in China, involving 14 IVF clinics and a total of 1,212 patients aged between 20 and 37 years, reported similar unfavourable results that were published in the prestigious New England Journal of Medicine.
Hence, based on the latest scientific and clinical data, serious doubts about the medical benefits of PGS have emerged, and current stringent regulation by MOH is thus justified.
 

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