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‘The white coat and the cross’ - the witness of Dr. Lejeune

On January 21, 2021, Pope Francis declared Dr. Jerome Lejeune as “Venerable,” a step in the process of being declared a saint.

Lejeune is known for his research into the chromosomal abnormality, Trisomy 21, which is the cause of Down syndrome. He was a renowned scientist, and he was also a Catholic who dedicated his career to the defense of life.

Venerable Dr. Jerome Lejeune. The Lejeune Foundation.

Today he is recognized as a pro-life pioneer by doctors and other medical professionals. 

Among them is Dr. María del Pilar Calva Mercado, who was neither pro-life nor a practicing Catholic in her youth. But after studying for eight months with Lejeune in Paris in 1982, she underwent a powerful change of heart, leading to a conversion that would shape the trajectory of her life.

Dr. Calva agreed to speak with The Pillar about the life and legacy of Dr. Lejeune. 

This interview has been edited for length and clarity.

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How and when did you meet Dr. Lejeune?

I met Dr. Lejeune for the first time in person in July 1982. 

A few months before that - I don't remember exactly when - my genetics professor in Mexico wrote Lejeune a letter, asking that I be allowed to do my undergraduate medical thesis with him.

My professor recommended that I study with Lejeune because of the high scientific status he had. At that time he was recognized as the best scientist in the world. 

As it happened, neither my professor nor I shared Dr. Lejeune's line of thought regarding the defense of truth, concerning human life and the family — I didn’t even know about his positions on those things.

I had more of a very materialist, very pragmatic way of thinking. And I was interested in studying with Lejeune because of the high scientific credentials he had. 

He accepted me to study with him for eight months, and so I went to Paris.

I met him in the early days of July 1982. 

My first impression was that I was with an extremely intelligent man, but his eyes conveyed a lot of humility. I discovered him to be a wise man - a person who knew a lot, but who could make that knowledge understandable for simple people. I later saw that in practice, working professionally with him.

At first, I was excited to be there, because I thought I was going to learn a lot. I was actually disappointed once the work started, because he assigned me laboratory work as a thesis topic, which I have never liked. I like being with patients, examining them, not sitting there in front of a microscope.

But we clicked quickly because I saw that he loved doing consultations — being in contact with people.

Today, I would use another word to describe it — I would tell you he is a saint. But at that time I didn't have that word in my vocabulary, so I would have said he was a wise man.

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It sounds like he changed your perspective on a lot of things.


When I arrived in Paris, I thought that I was going to write a good thesis, that I was going to learn a lot from someone with high credentials — but I never thought that I was going to have a conversion of heart and mind. 

I never thought I would become committed to defending life. And I certainly never thought about a conversion! 

And how did he achieve this? With his testimony. He was a very coherent person. He never asked me how I lived, if I was in a state of grace, if I went to Mass on Sundays. 

We never touched on those topics.

Instead, it was simply seeing his daily life, being his shadow, both in consultations with families who were doing well, and with others who were not doing well.

It was impressive how he helped families fall in love with their disabled children in the hospital, from the beginning, even if they saw the suffering they were going to go through.

These were little ethics lessons that he was giving me. 

I studied at a Catholic university, but there they taught me how to prescribe contraceptives, they taught me the mentality of the culture of death. 

But he told me that he couldn't do a prenatal diagnosis. He told me he wouldn't do an abortion, but that he also would not cooperate with it [through a prenatal diagnosis], because from a document he sent with a genetic report, someone else would decide to do an abortion, and that was cooperating with evil.

When he took those positions, he began to lose donations. 

He did very important research despite the few resources he had, but he preferred to be faithful to his conscience and the truth, rather than having more resources.

It is true that he would have loved to have more resources to collaborate in the healing of many children, but he did not give in.

That commitment touched me, it changed me totally.

I remember him telling me that it was scientific cowardice to think that medicine was about eliminating the sick if we couldn't eliminate the disease. And any doctor knows this, with faith or without faith: medicine is meant to end diseases, not the sick.

When I first started working for him, he went on trips to Rome, specifically to the Vatican. 

At that time... I had this vision that the Holy See was the most misogynistic state in the world, ruled only by men. 

So he told me that he was going on these trips and I said, “Well, hope it goes well,” nothing more. 

On Monday mornings, after those trips, he would leave on my desk the papers he had presented to the Pontifical Academy of Sciences, and on those trips he used to see John Paul II.

I remember that the second document he left me was called, “Biology, Conscience and Faith.” 

After reading that text, I experienced something: The vestiges of Catholicism and faith that were within me, along with some minimal fear of God, came together with my clinical activity and I began to be more interested in things like faith and spirituality, and observe that part more in our medical consultations.

After those eight months I told him: “Doctor, you changed me. I came here thinking that you put on the white coat from Monday to Saturday, and took off the crucifix, and then on Sunday you put on the crucifix and took off the white coat. But you have taught me to wear the white coat and the crucifix at the same time.”

I told him that I was afraid to return home because I was in a very liberal environment, I had everything already very well established and I thought that it was going to be difficult for me to return to that environment. 

At that moment he told me, “Someday you will come back to me,” and he told me that he would continue sending me everything he wrote, and I think that even the last thing he wrote before he died reached me, so I am very blessed.

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You did return to work with Lejeune again, right? When was that?

I returned to Mexico, I studied clinical genetics, and in 1985 an earthquake occurred in Mexico. Many hospitals collapsed. Mine didn't collapse, but it was so bad that we were never able to get into it. 

The French government helped by giving scholarships to medical residents who had been stuck halfway through our studies. 

So in September 1986 I returned to work with Dr. Lejeune, until 1988, doing a specialty in cytogenetics, which is the study of chromosomes, something that today would be studied directly in genomics — cytogenetics is like seeing the cover of the book, genomics is like reading the book.

I did cytogenetics studies and I worked with him, mostly in the clinic.

Lejeune is the father of modern genetics. And thanks to his discoveries, patients with Down syndrome are seen with dignity.

A long time ago, John Langdon Down had described some characteristics of children with this condition: slanted eyes, heart disease, short hands. But the reason for their condition was not known.

Because it was thought to be a consequence of syphilis, many families were embarrassed to go out with their children, because it was seen as a sign that they had syphilis. Families would not let their children leave the house, or if people saw them on the street, they would move to the other side of the sidewalk.

You know, Lejeune’s work went beyond chromosomal conditions - he also had important research on the genetic causes of cancer. 

And he also collaborated with John Paul II, much more than people realized. Many of the documents he shared with me were source material for Fides et Ratio. 

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Which of his virtues stood out to you the most?

I have always had a hard time answering that question.

If I start with the theological virtues, he was a person of great faith and much hope. 

He lived charity in works, in how he treated his patients and all the people around him, from the lady who cleaned the bathroom in the office, to the doctors and researchers who opposed him — who supported the culture of death. 

He always spoke very calmly, with great respect, but without conceding the truth.

But where you saw the most charity was in how he treated “the least of these,” as he called them. He truly lived that phrase from the Gospel: “Inasmuch as you did it to one of the least of these my brothers, you did it to me.” 

He always said that his patients had greatness of spirit. He always saw that true greatness was in littleness.

I remember that while caring for patients with Down syndrome, he would use a microscope which had two pairs of lenses. He would sit with a patient, and he with a pair of lenses and the child with another pair, and he began to count the chromosomes with them and when they reached 21, they would see that there were three.

Dr. Lejeune would explain things to them. And the patients would say: “Ah, that's why I'm so special.” 

He always sought to dignify them, and to convince parents to lovingly accept their child, who had been born with a genetic disorder.

In the ‘80s, abortion was already legal and paid for by social security in France. In addition, if there was an error in prenatal screening and a child was born with a genetic condition, parents had a period of time in which they could legally leave their child in the maternity hospital.

So when Dr. Lejeune saw that one of those cases had occurred, he would always say, “I will deliver the result personally.” 

After half an hour of talking with the parents, they usually came away in love with their child, and determined to move forward.

That commitment — living “what you did for the least of my brothers…” was the mark of his life.

It was a great sadness for him to see his scientific discovery misused. 

Today in many European countries, there are many people who have never seen a child with Down syndrome. Dr. Lejeune saw that, and it hurt him a lot, because he didn't want his discovery to serve as a death sentence; he researched Down syndrome seeking to dignify, to help.

He even created an organization that was meant to help mothers whose children had prenatal diagnoses, to give them options, so that they would choose life.

Dr. Lejeune knew that his stance was going to cost him, it probably even cost him the Nobel Prize. 

The World Health Organization once invited him to give a conference, in which he was asked to affirm that life begins at implantation, that is, 14 days after conception, which was the prevailing medical view. But he saw that was the time to tell the truth, and so he defended the scientific truth that life begins at conception. At one point, he added: “This looks like the World Death Organization, not the World Health Organization” because he knew why they did not want him to defend life.

But he was consistent until the end. He didn't say, “Well, I'm going to tell a little lie, but this way I can continue to influence and help.” No, no. He always believed in telling the truth until the end.

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What was his spiritual life like?

There were things that, at that time, I did not understand or did not see so clearly because I was still in the process of conversion. 

He was always very respectful, we didn't talk about faith — or maybe I didn't take the hint.

But now I think about how often I saw him in his office, in total silence, with his hands together and his eyes closed. At that time I didn't give it much importance, now it seems clear to me that he was praying.

Something that I can tell you that always impressed me a lot was his simplicity.

After he died, I visited his grave with his widow and it was a simple headstone. 

Normally, he didn't ride in a car, but used an old bicycle. It looked like something from the Second World War... and he always brought a plastic poncho in case it started raining.

He lived the virtue of poverty a lot. He always dressed impeccably, but after a while with him you realized that he didn't replace his clothing much, that maybe he had two or three suits.

Humility was another virtue that he lived and it is a virtue that a good scientist needs. As a scientist you always have to be willing to admit that you are wrong. If there is no humility and you say that you know everything, that there is nothing more to study, you are not a good scientist.

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Wasn't it intimidating to work alongside such an intellect?

Look, I come from a very intelligent family. My dad was the first doctorate in biochemistry in Mexico; my brother, the first PhD in molecular biology; my mother was the third mathematical physicist to graduate from a university at a time when women generally did not study.

So really, my parents' friends were always intellectual, the conversations at meals were always about intelligent topics. I was very used to these environments, but Dr. Lejeune was also so humble that he didn't intimidate you. I never saw it that way.

There are people who, with their way of speaking, trample on others or explain everything in a complicated way and nothing is understood, but he was the other way around. He could explain the most complex things to a child, he would sit in the office and answer all their questions in the simplest way. If he had a foreign patient, he tried to speak in their language so that they felt comfortable with him.

He was always so cordial, so loving, that it was not possible to feel intimidated with him.

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Saint John Paul II once said that Dr. Lejeune was the most intelligent person he knew. What was the collaboration like between the two of them?

When he made trips to Rome in my first stage working with him in the early ‘80s, he went to the Pontifical Academy of Sciences. The documents of this academy are not magisterial, it should be clarified. It is a means for great scientists from various areas to present their dissertations and have discussions on these topics and to keep up-to-date with discoveries and trends in science.

So with some frequency he went to the academy meetings and had breakfast or met with the pope. At that time, the Pontifical Council for Health and the Family Council also existed, and they realized that they were beginning to address issues of life ethics, but in a very specialized and very practical way and only insofar as they related to health and the family.

So John Paul II entrusted him with the task of starting the Pontifical Academy for Life. Lejeune is the one who drafted the declaration of pro-life belief that one must take to enter the academy - the promises about what it meant to be a member of the academy, to be an apostle of truth and a servant of life.

In December 1993, he told me that this very aggressive cancer had been detected. In February 1994, he became the first president of the Academy. He died on April 3, 1994, which was Easter Sunday.

Not only did he collaborate with John Paul II, but with Paul VI he was part of a commission of scientists considering the topic of Humanae Vitae and he was also part of the delegation of the Holy See at the Population Conference in Bucharest in 1974.

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Living that Christian coherence led him to ostracism within the scientific community. How did you see him deal with that?

I never heard him complain. I never heard him say that he didn't have this or that reagent due to a lack of resources. He ran his office with the bare minimum. His office looked almost like a kitchen because of the mosaics it had, it had a very simple desk.

He was consistent. He did not do prenatal diagnoses and did not research better techniques for diagnosing and then cutting off heads. He dedicated himself to understanding what was happening metabolically with children and made the most of everything he received.

I never saw him complain and he always forgave. I never heard him say, “This person did this to me.” He was always very firm in his principles, but very soft in his ways. He always spoke very sweetly but with great coherence. It is as Benedict XVI says in Caritas in veritate: he who loves cannot love without the truth, but the truth must be presented with charity.

He always had a very deep peace. Now I can see that it was a spiritual peace. He knew how to respond to these attacks and difficulties with great peace despite the adversities.

His daughter Clara wrote a biography of him and says that they lived near the Sorbonne and sometimes student activists using megaphones wished him dead and said, “Let all Dr. Lejeune's monsters die.” 

Even on the day he died, they painted graffiti celebrating his death…And he always carried all this with peace.

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What do you think Dr. Lejeune’s greatest legacy was?

For a parent, having someone who understands them changes the way they see their child, right? His commitment to helping parents fall in love with their children with unconditional love.

If one defends the little ones, God blesses us, but he blesses us by becoming a sign of contradiction. Jesus Christ did not deceive us, he told us that we would be persecuted in his name.

So, I think that is his legacy - his defense of the truth, showing that faith and reason are not incompatible and that one can wear the white coat and the cross.

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