Everyone knows Chapter 3 of Genesis, which relates the Fall of man in the Garden of Eden. The serpent tempts Eve to eat fruit from a forbidden tree, the Tree of the Knowledge of Good and Evil.

She, in turn, entices Adam to do the same. Afterward, they both realize that they are naked, and God banishes them from the garden.

Anytime I am in Mass and the reading stops before the end of Chapter 3, I want to stand up and shout at the lector, “Keep going!”

The last verse of the chapter mentions the other tree, the forgotten tree, the Tree of Life. God expelled man and set the cherubim and the fiery revolving sword to protect the Tree of Life, lest man eat of it and live forever.

In her book The Second Tree: Stem Cells, Clones, Chimeras and Quests for Immortality, Elaine Dewar, an investigative journalist, wonders where the cherubim and sword have gone. She regrets that scientists are “swarming all over the tree of life ... grafting on new branches, meddling with the tree’s molecules.”

That was more than a decade ago. It has gotten so much worse since then.

One of the newest assaults on the Tree of Life is the announcement that scientists in China have used a cutting-edge DNA-editing process to alter the genetics of viable human embryos. The technique is called CRISPR, short for “clustered regularly interspaced short palindromic repeats,” which is, of course, a meaningless jumble of words to the layperson.

What every layperson does need to know, however, is that CRISPR is a powerful tool to modify the DNA of organisms more precisely than in the past. Scientists have begun to use CRISPR to alter the genetics of everything from yeast to human cells.

In morally good applications, CRISPR is great news for research into disease. Ideally it will be used to provide gene therapy for existing patients. It may revolutionize treatments for everything from cystic fibrosis to Huntington’s disease. CRISPR could be the vehicle to cure many diseases for people who are suffering.

However, modifying human embryos with CRISPR, even in an attempt to cure, is another thing entirely. The scientists in China intentionally created six embryos with genetic disease and then tried to fix the mutation. Previously, scientists used “non-viable” embryos, meaning their genetic makeup was so abnormal that they could not have grown into babies, and the results were a failure. Only four of the 80 embryos had the intended fix, and there was evidence of unintended mutations introduced by the CRISPR process. The New York Times called it “collateral damage.”

The six healthier embryos fared better. One embryo had its mutation fixed in all the cells. Two embryos had their mutations fixed in only some of their cells. The technique did not work at all in the remaining three embryos, and there was still “collateral damage.” In one of the embryos, CRISPR caused a different mutation instead of fixing the intended target.

These results are being called “promising.” I call them a disaster. Not only were six human embryos created, manipulated and then destroyed in this process, but if the intent is to use CRISPR to create disease-free children, anything less than a 100% success rate is a total failure.

In addition, editing the DNA of embryos means that any modification will likely be incorporated in the sperm or egg cells of the resulting child. Using CRISPR, or any other genetic-engineering tool, on embryos means that any changes made will be passed down to future generations. Mistakes will not just affect that one child. Their children, grandchildren and great-grandchildren may be affected, as well. The same cannot be said of using CRISPR to treat existing patients.

The fact that modifying embryos creates germ-line changes is the reason many scientists are against tinkering with the genetics of embryos, even if it is for a therapeutic purpose. Prominent researchers, including those who developed CRISPR, have called for a worldwide moratorium on using the technology in human embryos because of the inherent risk to future generations.

The Catholic Church agrees. Dignitas Personae distinguishes between gene therapy that is for a single patient and germ-line modifications that can be inherited. Not only is it unethical to create and manipulate human life in a laboratory, but Dignitas Personae states, in regards to human germ-line modifications: “It is not morally permissible to act in a way that may cause possible harm to the resulting progeny.”

Then there is the slippery slope from going beyond editing embryos to cure disease to modifying embryos by design. There is real and growing concern that once CRISPR is perfected for fixing genetic mutations in embryos, it will be used to enhance embryos with whatever traits parents desire.

In a recent opinion piece, two prominent genetic researchers called experimentation on embryos with current genetic-engineering techniques “dangerous and ethically unacceptable,” and they warned: “Many oppose germline modification on the grounds that permitting even unambiguously therapeutic interventions could start us down a path towards non-therapeutic genetic enhancement. We share these concerns.”

History tells us that this particular slope is slipperier than a greased watermelon. Back in 1980 — before IVF was mass manufacturing, freezing and discarding human embryos — syndicated columnist Ellen Goodman argued for embracing the technology, insisting that abuses were unlikely.

She wrote about the opening of the first IVF clinic in the United States: “A fear of many protesting the opening of this clinic is that doctors there will fertilize myriad eggs and discard the ‘extras’ and the abnormal, as if they were no more meaningful than a dish of caviar. But this fear seems largely unwarranted.” All of those fears, and more, have come to pass. Goodman also insisted: “We have put researchers on notice that we no longer accept every breakthrough and every advance as an unqualified good. Now we have to watch the development of this technology — willing to see it grow in the right direction and ready to say no.”

So far, the scientific community at large has yet to say, “No” to anything related to the creation, destruction and manipulation of human embryos.

Bioethicist Wesley Smith, after reading another column by Goodman arguing for embryonic stem-cell research, wrote to her pointing out that she was supporting treating human embryos like they “were no more meaningful than a dish of caviar.” Goodman responded, “My lines have changed.”

Indeed. Which is why Elaine Dewar, after she lamented that scientists were swarming all over the Tree of Life, exclaimed: “How did this happen? Where will it end?”

It happened when we lost all regard for pre-born human life. It will end in a world where parents are pressured into “upgrading” their children with the latest enhancements via genetic engineering just so they can participate in society.

I have heard many times that this Gattaca scenario will not be so bad. Why not improve future generations if we have the ability? I always respond with The Three Graces. This masterpiece, painted by Peter Paul Rubens in 1635, depicts three naked women. They are extremely pale with fat, lumpy stomachs and thighs, and small breasts — the ideal female form for their time. What if the people of the 1600s had CRISPR to engineer future generations? What traits would they have chosen? Likely a genetic predisposition to obesity and skin cancer.

A better question is: What traits would we choose today that will make future generations hate us?

A voluntary moratorium is clearly not working, and society seems incapable of saying, “No” to unethical science that threatens the health and well-being of generations to come. It is past time for legislation in the United States and in countries like China that bans the germ-line genetic engineering of human embryos.

As Catholics, we must add human embryonic research to the list of life issues we are passionate about. We may not have a cherubim and a fiery revolving sword at our disposal, but it is still our charge to protect the other tree, the Tree of Life. The future of humanity depends on it.

Rebecca Taylor is a clinical laboratory specialist in molecular biology.

She writes about bioethics on her blog, Mary Meets Dolly.