Cardinal Alfonso Lopez Trujillo, president of the Vatican’s Pontifical Council for the Family – a panel appointed to advise the Pope on family matters – severely condemned all research on embryonic stem cells in an interview for the Catholic weekly Famiglia Cristiana in 2006: “Destroying human embryos is equivalent to an abortion. Excommunication will be applied to the women, doctors and researchers who eliminate embryos [and to the] politicians that approve the law.” He became the first high-ranking Vatican official to have proposed the Catholic Church’s highest remaining sanction for scientists involved in research on embryonic stem cells.

Anatomy research on cadavers

The call for the excommunication of scientists involved in one of the vital fields of modern science bears a significant meaning. It should at once be put into the context of similar ecclesiastical statements made over previous centuries. In 1300, Pope Boniface VIII issued the bull De Sepulturis which runs as follows: “Persons cutting up the bodies of the dead, barbarously cooking them in order that the bones are separated from the flesh, […] are by the very fact excommunicated.”

Many centuries ago, dissecting human cadavers was thus considered to be as morally abhorrent as today’s research on embryonic stem cells is to the present Roman clergy. Just as reducing the human body to a subject of medical research raised ethical issues in the past, researching embryonic stem cells presents a problem today. In both cases, one might say, it is a matter of violating the dignity of the human being by using it merely as an instrument for scientific progress.

Body snatchers

In the past, scholars performed most of their anatomy research on animals. The authorities only occasionally allowed them to study the cadaver of some executed criminal. Yet without extensive studies of anatomy on actual human bodies, although a highly questionable practice on moral grounds in the past, one could hardly imagine any progress being made in the field of medicine.

Because cadavers appropriate for dissection were so difficult to acquire, and it was impossible to advance the knowledge of human anatomy without them, the scientists of earlier times simply had to manage some way or another. While writing his fundamental book on the anatomy of the human body, which was released in the same year as Copernicus’s groundbreaking work on astronomy, Vesalius was always eagerly on the lookout for cadavers. Some of his memories remain gruesomely vivid: “I stored corpses dug out of graves or collected after public executions in my bedroom for weeks.”

Looking back through the history of medicine, one reads of numerous guilty verdicts given for the theft of cadavers for purposes of anatomical research. Thankfully, students of medicine no longer need to creep around cemeteries, digging out fresh cadavers, or wait for executions. (For a period of time, a rule applied in medical schools: a practical anatomy class only took place if students managed to acquire their own cadaver.) Today, however, society has reached a consensus on the conditions that allow a human body and its parts to be used for scientific and therapeutic purposes after a consenting person’s death.

The Church changes heart in 1869

Could a similar attitude be adopted towards research on embryonic stem cells? As long as influential people and institutions, among which the Roman Catholic hierarchy and the Church are naturally prominent, persist in regarding a single fertilized cell and a completely developed human being as equals, opinions will continue to clash. Nevertheless, a number of Catholic theologians believe that the Church’s attitude will soon change.

Today, it is largely forgotten that the Church has only claimed the same rights for a person and a fertilized egg for less than a hundred and fifty years. It was only in 1869 that the Catholic Church took the view that the life of an individual begin with fertilization. That was when Pope Pius IX eradicated the already established distinction between an unformed fetus, still uninhabited by the soul, and a fully formed being possessing all the human dignity that belongs to a person. A similar distinction between different phases of fetal development, as it happens, was drawn many centuries ago, but only because the mindset for it had already been established in Greek philosophy.

An error in the translation of the Bible into Greek

The discussions about the moral status of the human embryo were heavily influenced by the following paragraph from the Second Book of Moses (Exodus 21), dealing with physical injuries:

And if men strive together, and hurt a woman with child, so that her fruit depart, and yet no harm follow; he shall be surely fined, according as the woman’s husband shall lay upon him; and he shall pay as the judges determine. But if any harm follow, then thou shalt give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burning for burning, wound for wound, stripe for stripe!

In the translation of this paragraph from Hebrew into Greek a small error was made. Where the original states that only financial compensation is required in the case of an abortion if the mother is left unharmed, the translators decided to interpret the message in a way which implies that the milder penalty of a fine should only be given if the aborted fetus had not yet acquired a “form”, that is, a human form.

The criterion for distinguishing between these degrees of o wrongdoing was transposed from the mother (harmed or unharmed) to the fetus (having form or not having form). The distinction between a formed and an unformed fetus fit well with the widely established Greek idea of the nature of the soul developed by Aristotle. According to Aristotle the soul of a living thing is its form. The interpretation thus prevailed that a formed fetus already possesses a soul. A formed fetus was therefore granted the rights due to a person, while a formless one was merely of economic significance.

The formless and the formed embryo

In the thirteenth century, Thomas Aquinas tried developing a synthesis between the traditional Christian perception of the world and the newly discovered Greek knowledge which, in that period, came to Europe through translations of Aristotle’s work. According to Thomas, an embryo does not initially possess a human soul, but merely a form which is also typical of other living beings and enables growth and development. It is only when an embryo develops to the point where it resembles a human being that the rational human soul inhabits it, at the same time making it a human being.

Thomas’s interpretation was adopted by the Catholic Church and a similar attitude was also assumed by other monotheistic religions. Until 1869, the Catholic ecclesiastical code distinguished between a formless embryo still devoid of human soul, and as such not a human being, and an already formed fetus, possessing all the features of a human being. Most religions have retained this stance until this very day, so that neither Islam nor Judaism oppose research on embryonic stem cells.

For centuries it was believed that the fetus only develops into a human being when it obtains a soul by taking on human form. So what was it that inspired the Catholic Church to change its moral stance a century ago? Surprisingly, new scientific discoveries about the foundations of reproduction were responsible.

How does an embryo become a living being?

In the eighteenth century, an important debate arose among naturalists on the mechanisms involved in the creation of individual living beings. With the help of the microscope, they discovered that the early embryos of different living organisms look alike, only later developing into distinctly different living beings. So, how can embryos, composed of merely a few cells, know what they have to become?

One theory was that all embryos were completely developed from the very beginning. This meant that all their individual characteristics were already established from the moment an embryo came into being. Pregnancy was considered to be merely a period of growth. This concept of understanding the development of individual living beings was taken to extremes by the philosopher Nicolas Malebranche. If individual offspring were already fully formed inside their mother, this logic would imply that they were also such in their grandmother and all the way back to Eve, she being the first in line of all women ever to bear children.

According to this theory, Eve contained all living beings; they only had to await their actual realization. This is also how Malebranche explained the spread of original sin spread to all mankind. When the first couple broke God’s commandment in the Garden of Eden by eating the forbidden fruit from the Tree of Knowledge, all mankind was already present within Eve’s body.

As decades went by, naturalists developed this so-called “preformation theory” until their focus shifted from the actual visual similarity between a fetus and a fully formed living being to the presence of a plan which dictated the development of a living being. This idea was the predecessor of today’s genome concept.

Problems with the precise definition of the beginning

Similar idiosyncratic interpretations, inspired by ideas such as Malebranche’s preformation theory of the embryo, can lead to a rigid defense of the hypothesis that a fertilized egg should already be considered a human individual. However, defining the very moment of fertilization presents some difficulties. When exactly is this new individual supposed to come to life? The new genotype within a fertilized egg is only fully established some 24 hours after a sperm has penetrated the egg. The genes of the new genome do not begin to express themselves until a few days later when the embryo is already made up of several cells.

It is perfectly clear that the embryo at this stage has no form which in any way resembles that of a human being. It is merely a clump of cells, completely incapable of independent development. Even later after the point of fertilization the embryo can split in two, creating identical twins. This occurs only once for every few hundred births, but we do not take it to mean that each twin subsequently has half of the egg’s original form and thus half a soul. The idea of one human “soul” per egg is therefore too simplistic. A fertilized egg alone cannot be considered an individual; it should rather be viewed as the matrix of tissue from which individual fetuses may develop.

Just as we succeeded in reaching a social agreement concerning our treatment of the dead, and thus the way in which the body and organs of the deceased may be used, we have to come to a consensus in terms of our attitude towards embryonic cells. The scientific community has already set up its protocols while the majority of the general public all across the world has given its support to carefully regulated research on embryonic stem cells. Now is the perfect time for the Catholic Church to reconsider the moral status of embryonic cells and silence the ongoing reproaches against its obstruction of scientific progress.