This is a public lecture on science, medicine and Christianity, with the aim to encourage a constructive and open conversation between the sciences and the humanities, and in particular between scientists, theologians, and ethicists. The lecture has been named after Marguerite D’Youville, a founding figure in Montreal’s history, who helped establish Montreal’s first hospital and the order of sisters, namely the Sisters of Charity of the Hôpital Général or Grey Nuns (as they are commonly known),