The Servant of God Jérôme Lejeune

Jérôme Lejeune in his laboratory« Just one sentence, spoken by Jesus himself, will suffice to determine our behaviour : ‘Whatever you do for the least of my brethren, you do it for me. » Jérôme Lejeune

On the 3rd April 1994, Easter morning, Prof. Jérôme Lejeune was summoned to Almighty God. The very next day Pope John-Paul II sent this message to the Cardinal Archbishop of Paris : « That the Heavenly Father should have summoned him on the very day of the Resurrection of the Lord must surely be no mere coincidence, but in itself a veritable sign.»


A doctor by calling, by necessity a research worker

Born in 1926 at Montrouge, Jérôme Lejeune very soon wished to become a doctor.

Jérôme Lejeune childJérôme Lejeune in his gardenJérôme Lejeune with a patient

Educated in the classics, he came to be passionately interested in many things besides: the theatre and astronomy, music and mathematics ; and when, towards the end of the war, he had to choose a career, he immersed himself with ardour in the study of medicine.

In 1951 he became an assistant to Professor Turpin, and concerned himself with patients who were known at the time as mongols.

From that moment onwards, greatly upset by the condition of his patients « deprived of that fulness of life which we call freedom of spirit », Jérôme Lejeune vowed his existence to their service and put all his mind and heart into looking for a successful treatment : «Compassion for the parents is a feeling which every doctor must have. Anyone who can tell parents that their child is gravely affected in this way without, at the same time, feeling broken-hearted at the thought of their terrible anguish on hearing the news is not worthy of our calling.»
In 1958 on examining the caryotype of a young boy he discovered the origin of mongolism: an additional chromosome on the twenty-first pair.

Jérôme Lejeune at workJérôme Lejeune discovers trisomy 21 gene

It was only after the French Academy of Sciences published, on 26th January 1959, a paper by Lejeune, Gautier, and Turpin concerning three mongol children that little by little the international community took cognizance of the significance of this discovery.

He now began to receive innumerable prizes and was awarded membership of several international academies and institutions. On 6th June 1959, some months after the first publication, he wrote in his journal : « If only God willed that we could finally do something for these children whom I have been observing, powerless to help, these well nigh 10 years, what an immense joy that would be.» If this remarkable discovery made him ‘the father of modern genetics’, more than anything else it made him aware of the urgency [of finding the cure], a need he never lost sight of until he died.

Jérôme Lejeune with a young patient


Witness for God, witness for men.

In a truly poetic spirit Jérôme Lejeune contemplated his entourage. Vividly aware of the mysterious beauty of creation he pledged himself to combat the shortcomings of nature itself, particularly when its victims were fellow human beings. Working to re-establish the lost harmony now afflicting them, to treat and to cure them, to defend in the public arena the dignity and the human life of his patients, all this became his primary objective. And when the medical profession itself proposed to overcome the disease by killing the patient, he could not accept this utter absurdity and so became for his patients a truly indefatigable champion.

Jérôme Lejeune gives a lectureJérôme Lejeune with trisomic babyJérôme Lejeune with John Paul II

In his consultations at the Necker Hospital for Sick Children his attention for each one of his 9 000 patients, from all over the world, was very striking to all those who came his way.

Alongside the research worker, the doctor, and the valiant defender of life itself, we should never forget the Christian, also, nourished as he was by a Faith at once demanding and aflame with charity, a Faith which he lived from day to day. He bore witness to the Gospel with his knowledge, understanding, and expertise, so demonstrating beyond cavil the perfect compatibility of natural science and Christian Faith. His lucid reply to the common query was simply this : ‘how could there possibly be a contradiction between what is true and what is seen to be true ? For it is always the second which arrives late’. When he was already a member of the Pontifical Academy of Sciences, the Pope appointed him first president of the Pontifical Academy for Life.

The Cause of his beatification and canonization was opened on 28th June 2007.

Jérôme Lejeune portrait