Since the early days of in vitro fertilization in the 1970s, embryologists and developmental biologists have held themselves to a self-imposed norm of 14 days for growing human embryos in vitro.

This 14-Day Rule, as it is called, has been a macabre attempt by the scientific community to place a face-saving limit on an obviously questionable type of scientific research. I say macabre because the rule designates the outer limit that embryos are allowed to live in a laboratory.

Fourteen days is the kill line. The rule guarantees that scientists, after performing whatever manipulations they so desire on human embryos, will destroy them after 14 days (see 1979, U.S. Government advisory report on IVF, p. 107, No. 4).

Nor has the Rule required any moral restraint, since till very recently 14 days was well beyond the threshold that scientists were capable of growing human beings in a laboratory.

As you might suspect from the title, the 14-Day Rule is now on the chopping block. Before reviewing the present situation, allow me briefly to comment on the philosophical reasoning used to justify drawing the line at 14 days.


Specious Philosophical Arguments

Those familiar with the mischief that Catholic moral theologians have caused in the post-Vatican II period will not be surprised to learn that the justifying arguments for the 14-Day Rule came from decades-old fallacies proposed by these same moralists.

Jesuit Father Joseph Donceel, for example, argued in 1970 that a human soul could not exist in a highly undifferentiated body like that of an early embryo. And so, he said, he “felt certain” that no human person is present until — at earliest — the beginning of the development of sense organs, the nervous system and especially the cerebral cortex. And this isn’t for several weeks after fertilization.

Even more influential was Salesian Father Norman Ford, who argued in the early ’80s that although the appearance and activity of early embryos convinced him that human life begins at conception, he was confident that human persons don’t begin before 14 days. Before that time, he said, the embryonic body still has a capacity for twinning (i.e., dividing into identical twins).

At 14 days, the embryo begins to develop a “primitive streak” — a faint line down the center of his body axis marking the start of the process of “gastrulation.” The relatively undifferentiated cells of his delicate body begin to differentiate into distinct cell types (the dark line represents the visible precursors of the spinal cord and the brain), and the capacity for twinning ceases.

If before this point, Father Ford argued, a developing human being still has the potential to become two or more human beings, then it must not yet be an individual (i.e., a single individuated entity), and if not yet an individual, not yet a person — for whatever else a human person is, it is an individual of the species Homo sapiens.

This argument from twinning has been refuted multiple times over the years (see Robert George and Patrick Lee’s devastating refutation here), so I won’t rehearse its inadequacies again.

Suffice it to say that scientists and their ethicists looked at the argument and said, Let’s not grow human beings beyond this point — knowing, of course, they had no ability to do so.

Well, it now happens that techniques for embryo cultivation are advancing. And the scientific community — surprise — is beginning to ask whether the 14-Day Rule is still adequate.


Extend the Kill Line!

Two essays published in 2016, one in Nature Cell Biology, the other in Nature, report labs successfully growing human embryos in vitro to 13 days. The teams found that if they used a certain nutrient-rich “cocktail,” the embryos lived long enough to begin to attach themselves (a kind of artificial implantation) to the bottom of the petri dish, even in the absence of maternal uterine tissue. And they exhibited developmental milestones that only implanted embryos ever achieve. In the end, however, the teams destroyed the embryos “in accordance with the 14-day rule.”

Now that scientists are approaching the fateful line, they’re flirting with moving it from 14 to 28 days. They tell us that during the third week of human development remarkably interesting milestones take place that they are eager to observe in vitro, such as — wonder of wonders — the very milestones that marked the reason not to advance beyond 14 days’ development for the last 40 years, namely the events of gastrulation.

Further, advancements in CRISPR technology are allowing scientists to understand better the process by which a tiny embryo embeds himself into his mother’s uterine wall (implantation). But, they argue, implantation doesn’t begin in utero before the second week. So to understand it better, we need to go beyond the second week.

Moreover, in 2017 a lab reported using CRISPR to destroy the activity of a vitally important protein in several human embryos and then watching those embryos developmentally fail and die. The fascinated scientists say they want to study the activity of other such proteins on early human development, but may be hindered by the 14-Day Rule.

And so, in the last two years, numerous voices within the scientific community have been clamoring to revisit the Rule (see 1, 2, 3, 4, 5, 6).


Need for Pro-Embryo Public Policy

Note well that till now, defenders of embryo-destructive research in the U.S. have stymied every federal effort to introduce sensible legal restrictions on embryo experimentation. Astonishingly, there are no federal restrictions in the U.S. on what scientists may do to human embryos, although thanks to President George W. Bush, certain forms of destructive experimentation receive no federal funding.

In the face of the disturbing momentum for extending the 14-Day Rule, the most conservative suggestion to come out of a meeting of 30 scientists and ethicists in May at Rice University was to “keep the 14-day rule in place” and to introduce “a special petition” process for those who want “to make an exception.”

In other words, leave the kill line where it is (for now) and grant extensions on an ad hoc basis to those who ask for more time.

The scientists involved ask us to trust they will make decisions according to what’s in the best interests of the community. But they exclude from the human community members at the embryonic stage of development. So we need to say to them: “We don’t trust you!” And we need to say why.

Asking the scientific community to police itself in embryo experimentation, as it has for four decades, is like asking foxes to police themselves in the chicken coop.

We need sensible federal legislation protecting the lives of human beings at the embryonic stage of development.

But since doing so will have negative ramifications for the liberties secured by Roe v. Wade and on the profits of the fertility industry (in 2017 alone, the private equity data tracker, PitchBook, tallied more than $178 million flowing into to startups in the fertility industry), pro-lifers will need to remain resolute.