Denver Newsroom, Mar 18, 2021 / 17:04 pm
New "models" of early human embryos that cannot grow into full human beings provoke ethical questions about whether they are human beings. One ethicist warns that research should be halted out of caution until more is known, because of the ethical dangers and temptations in the experiments.
"Scientists face the perennial temptation to depersonalize early human life, and to treat embryos as objects. Human beings are so sacred, that we must particularly reverence them in their origins, in the way they come into the world," Father Tadeusz Pacholczyk, a National Catholic Bioethics Center staff ethicist with a background in medical research, told CNA March 18.
"Researchers should err on the side of caution, because it remains always and everywhere wrong to create young human beings in petri dishes or laboratory glassware," he said. "Doing so indicates a disordered eagerness to manipulate early human life and a willingness to exploit our own human offspring at the earliest stages of their existence."
Two different research teams have created human embryo-like entities by creating hollow balls of cells that resemble blastocysts, called blastoids. The blastocyst stage is normally about five to six days after conception, at which time the developing embryo has rapidly dividing cells, according to the Mayo Clinic.
"The recently-reported human blastoids are pieced together out of stem cells, and at this point, they appear to be very embryo-like, though the jury is still out on whether they could ever be fully functional or complete human embryos," Pacholczyk said.
The models are different enough from naturally conceived embryos that they will never become a viable fetus or baby, but they are very close to functioning like the early stages of a human being, National Public Radio reports.
The research could contribute to understanding how a single cell grows into a fully formed human being, and could help develop treatment for genetic diseases and prevent birth defects, miscarriages, or infertility problems.
The exact nature and ethical status of the models themselves is unclear, some observers said.
Kirstin Matthews, a fellow in science and technology policy at Rice University, told NPR she was concerned about "growing these sort-of humans in a test tube and not even considering the fact that they are so close to being human."
Pacholczyk was similarly concerned.
"One of the ethical questions around such experiments is whether researchers may actually be making a handicapped, but genuine, human embryo, a young human that is doomed to death as he or she grows because of various defects in the way they were originally constituted by researchers," he said, comparing the experiments to creating a child with a serious defect that kills them at a young age.
"If it were true that researchers are producing 'disabled' human embryos, entities that genuinely partake of our human form and essence, this would involve serious moral objections."
"Because we don't know yet whether we are creating crippled embryos in this way, we should be careful, and not perform these experiments using human cells," he said. "Rather they should be done exclusively in animals, including non-human primates, to help us figure out, with reasonable certainty, whether any human entities we might later make would be human creatures or not."
Jun Wu, a molecular biologist at the University of Texas Southwestern Medical Center in Dallas, led one research team's experimental model development, while Jose Polo, a developmental biologist at Monash University in Australia, led a different team.
Polo's team created blastoid models from adult skin cells, while Wu's team created models using a combination of induced-pluripotent stem cells from adult human cells and human embryonic stem cells. The use of human embryonic stem cells has drawn ethical scrutiny from critics, including Catholic critics, because the cells are derived from the destruction of human embryos.
Insoo Hyun, a bioethicist at Case Western Reserve University and Harvard University, told National Public Radio that the models are so close to being a human embryo that they raise "a very interesting question of, at what point does an embryo model become a real embryo."
"This work is absolutely unnerving for many people because it really challenges our tidy categories of what life is and when life begins," Hyun continued. "This is what I call the biological-metaphysical time machine."
In Pacholczyk's view, the experiments described extend a mindset accepting of in vitro fertilization. The Catholic Church has long said this "is never acceptable as a way to engender new human life."
"Regrettably, developmental biologists, such as Jacob Hanna at the Weizmann Institute of Science, are rationalizing precisely this kind of embryo experimentation by saying that researchers have already been destructively studying early embryos from IVF clinics for so long that there shouldn't be anything wrong with it," the ethicist added.
"He is advocating a very disturbing idea, namely, that of growing embryos and/or embryo-like entities 'until day 40 and then disposing of it'," said Pacholczyk. "He proposes, 'Instead of getting tissues from abortions, let's take a blastocyst and grow it.'
Hyun, one of the embryo model researchers, agrees on the need for clear ethical guidelines. However, he supports revisions to an international guideline that allows embryonic human experimentation on embryos up to 14 days old. He wants more exceptions "case by case in an incremental fashion," he told NPR.
There is "growing pressure" to eliminate the 14-day rule in order to grow embryos for longer periods, Pacholczyk told CNA.
