Jérôme Lejeune

In July 1958, within Professor Turpin's laboratory and in collaboration with researcher Marthe Gautier, Jérôme Lejeune identified the presence of a supernumerary chromosome on the 21st pair in a child suffering from mongolism. This major discovery was published on January 26, 1959, in the Comptes rendus de l'Académie des sciences under the signatures of Lejeune, Gautier, and Turpin. For the first time in the history of medicine, a scientific link was established between an intellectual disability and a chromosomal anomaly. This anomaly is now called "trisomy 21." This discovery earned Jérôme Lejeune immense international recognition. In 1962, he received the prestigious Kennedy Prize from the hands of President John F. Kennedy. In 1964, the first chair of fundamental genetics was created for him at the Paris Faculty of Medicine. He continued his research at the Necker-Enfants Malades Hospital, discovering other chromosomal anomalies, such as cri-du-chat syndrome (or Lejeune syndrome). However, starting in the 1970s, Jérôme Lejeune noted with pain that his discovery, which was intended to heal the sick, was primarily used to screen for them in utero in order to eliminate them through abortion. Faithful to his vocation as a doctor and to his Christian faith, he then committed himself publicly and forcefully to the defense of human life from conception. This prophetic commitment, notably against the Veil Law in France, led to him being gradually ostracized from the international scientific community and deprived of financial support for his research, thus renouncing a probable candidacy for the Nobel Prize.

The life of Jérôme Lejeune is a testament to the profound unity between science and faith. For him, the pursuit of scientific truth could not be separated from absolute respect for Creation and the dignity of every human being, as an image of God. His daily work with his patients was inhabited by heroic charity. He saw in children with Down syndrome "the poorest of the poor" and strove to heal in them the wounds of Christ, living fully the words of the Gospel: "Whatever you did for one of these least brothers of mine, you did for me" (Matthew 25:40). His moral integrity and his refusal of any ethical compromise, despite violent attacks and rejection by his peers, testify to his strength of soul and his Christian hope. Close to Pope Saint John Paul II, with whom he shared a deep friendship and a common vision for the defense of life, he was appointed by the latter as the first president of the new Pontifical Academy for Life in February 1994. Stricken with lung cancer, he passed away on April 3, 1994, on the morning of Easter, leaving behind an immense spiritual and scientific legacy.

The cause for the beatification and canonization of Jérôme Lejeune was officially opened on June 28, 2007, by the Archbishop of Paris, Cardinal André Vingt-Trois. The diocesan inquiry, conducted under the direction of Dom Jean-Charles Nault (then Abbot of the Abbey of Saint-Wandrille) and assisted by the lay postulator Aude Dugast, was solemnly closed on April 11, 2012, at the Cathedral of Notre-Dame de Paris. The boxes containing thousands of documents and testimonies were then sent to Rome, to the Congregation for the Causes of Saints. After the examination of the Positio and the positive vote of the theologians and then the cardinals, Pope Francis signed the decree on January 21, 2021, recognizing the heroic nature of his theological and cardinal virtues, thus declaring him "Venerable." For his beatification to be pronounced, the Catholic Church must now recognize a formal miracle attributed to his intercession.

The spirituality of Jérôme Lejeune rests on an absolute trust in God the Creator and on an unconditional love for the most fragile. He liked to repeat that "the quality of a civilization is measured by the respect it shows to the weakest of its members." His life of prayer, humble and daily, was anchored in his family life and his work as a physician. His legacy is perpetuated today through the Jérôme Lejeune Foundation, created in 1995-1996 by those close to him to pursue his three missions: to seek a treatment for intellectual disabilities of genetic origin, to care for patients through the Jérôme Lejeune Institute (created in 1997), and to defend the dignity of human life. In August 1997, during the World Youth Day in Paris, Pope Saint John Paul II insisted on visiting his grave personally at the Châlo-Saint-Mars cemetery to pay tribute to him. In June 2026, the Pope received members of the Foundation in an audience to mark the centenary of his birth, hailing him as a "man of science and wisdom."