The embryo had a yolk sac and a like-structure-called-protoplacenta, which simulates a state a real human embryo reaches about two weeks into development. It even produced hormones that caused a store-bought pregnancy test to register as positive.
In Jacob Hanna’s opinion, the artificial embryo wasn’t flawless, more like a simplistic blueprint. It had no potential of turning into a real baby. However, in 2022, when two students suddenly brought him to a microscope to show him a cluster of cells, Hanna realized his team had made a groundbreaking discovery in human development. Hanna, a professor at the Weizmann Institute of Science in Israel, also knew that the artificial embryo would raise important and difficult ethical issues.
At this stage, embryos are so tiny they can barely be seen with an ultrasound, and they can be kept alive in a lab for only a short time – not even long enough to be visible to the naked eye by 14 days. As for how long scientists decide to sustain them, a long-standing policy and set of regulations states that 14 days is the maximum time limit for keeping embryos alive in a lab.
Exploring the intricacies of creating an artificial replica of the natural process of human development from fertilized egg to living being. However, as scientists overcome technical hurdles, they are confronted with profound moral dilemmas. At what point does a replica become indistinguishable from a genuine human, and more critically, when should a laboratory experiment be regarded as a human being, with its rights and responsibilities?
That’s when the embryo fully integrates, essentially ceases to be a twin. “You become an individual,” notes Jeremy Sugarman, a professor of bioethics and medicine at the Johns Hopkins Berman Institute of Bioethics.
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The concept of in vitro fertilization, involving the storage of embryos until transfer or freezing around day five or six, was still evolving in the field. The committee concluded that 14 days was the latest timeframe to consider an embryo simply a clump of cells, without any capacity for individuality or personhood, since the brain and nervous system aren’t developed until after that milestone; they argued that, lacking a functioning nervous system, it’s an impossibility for an embryo to experience pain at this stage.
The Australian Embryo Research Licensing Committee has made a decision to treat more realistic human embryo models in the same way as real embryos, prohibiting them from developing beyond two weeks. In the US, federal funding for human embryo research has been banned since 1996, but there are no laws regulating experiments using either real or model embryos. “Is it an embryo at all?” was the question posed by Hank Greely, a law professor and director of the Center for Law and the Biosciences at Stanford University. Developing them further could potentially lead to complications, such as growing an extra head, though that alone wouldn’t disqualify someone from being human. Without a consensus on ethics, Hanna continues to try and develop his models up to day 21, roughly equivalent to the end of gastrulation. He has so far managed to grow them to around day 18.
Creating embryos in a lab from scratch is a complicated process. Trying to get pregnant monthly is simpler. In comparison, making embryos using unconventional means is a difficult endeavor. Currently, only one percent of these lab-made embryo models progress towards a developmental stage resembling an actual embryo, as Hanna explained. Because scientists are uncertain about how an embryo develops within the body, primarily during the nine-day-old stage, Greely pointed out that it’s uncertain whether these lab-made models mimic this process in the same way.
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There may be a promise—a hope, rather—of a human version of this experiment.
The reason behind this phenomenon remains unclear, suggesting that further research, particularly developmental research on embryo models, could potentially provide insights and shed light on this mystery.
Hanna’s system, among other goals, seeks to evaluate the safety of drugs using embryo models. Hanna also envisions a more futuristic application: growing embryo models up to day 60, removing their ovaries, and then using the eggs for in vitro fertilization. Since stem cells can be generated from skin cells, this system might potentially resolve the issue of infertility caused by older eggs, fore going the need for the more invasive aspects of IVF, which involve stimulating the ovaries with hormones and undergoing surgery to retrieve the resulting eggs.
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Professor Aryeh Warmflash, a biosciences expert at Rice University, is focusing on gastrulation, a process that doesn’t require detailed models of the placenta, he explained. “The more a model is perfected, the more potential issues come up,” he stated. However, his colleague Hyun expressed concerns that overly complex models could spark heated debates, considering the strong feelings many people in the country have about when life begins. Nevertheless, despite potential pitfalls, it’s likely that scientists will create increasingly realistic models to advance medical knowledge and tackle the many unanswered questions.
