Yvonne was the first born and largest at birth. She was to become the leader of the five – the elder-sister figure, mature, stable, serene. “Her” color was mauve, and she loved to wear pretty dresses in that color. She was the acknowledged “mother” of the group throughout the quints’ childhood. She was the one who looked after the others and was most respected by the others. Yvonne, along with Annette tended to boss the other girls around, but Yvonne’s bossiness was maternal (she oozed charm, rarely quarrelled, laughed and chattered a lot). Nurse Leroux had predicted that she was “destined to be a housewife”.

In 1952, Yvonne attended school at the Sisters of Assumption at Nicolet, Quebec along with her 4 sisters. The following year she separated from the others to study at the Congregation of Notre Dame in Montreal. After Emilie´s death in 1954, Yvonne moved with her three sisters to Montreal. Along with Cécile, she entered the Hôpital Notre-Dame de l’Espérance as a student nurse. After that, she decided to study art and sculpture. In 1961, she put that aside and announced that she intended to become a nun.

Yvonne never showed any interest in marriage. She tried to become a nun three times, but it was unsuccessful. In the early 70´s she moved out of her Montreal apartment and lived for a time with Annette and her family, and then bought a house nearby. By the end of the 70´s, she was best off financially of the three surviving sisters. She had little or no social life. She was never interested in male company, and apart from Annette and Cecile saw few people. In effect, she was a recluse. She did volunteer work in the St Bruno municipal library, but used to go directly from her house to the library and back to her house again, seeing no one.

By the early 90´s, Annette and Cecile had moved into Yvonne´s house to live together. They were living near poverty, their sole income a $700-a-month pension from Yvonne´s former job as a librarian. In 1998 the three sisters sued the Ontario government. Yvonne got to share $2.8 million with her two sisters – reparations for what they had been put through as children.

Yvonne died on June 23, 2001 from cancer.