Medical Genetics, at McGill, began in 1950 when the Department of Genetics at McGill and The Montreal Children's Hospital jointly initiated a Division of Medical Genetics at the Montreal Children's Hospital, under the direction of F. Clarke Fraser. At that time the discipline of Medical Genetics was still in its infancy: it consisted mostly of pedigree collecting to establish modes of inheritance and recurrence risks.

By 1960 the picture had changed dramatically. It was recognized that inborn errors of metabolism were not only useful tools for the analysis of normal biochemical pathways, but actually, or potentially treatable. A major extension in scope of the Department of Medical Genetics to include this area occurred with the advent of Charles R. Scriver, and the creation of the de Belle Laboratory of Biochemical Genetics.

At about the same time, the new ability to count and describe human chromosomes led to the creation of a Cytogenetics Laboratory (attached to the MCH), for the purpose of diagnosing certain syndromes of congenital malformations before and after birth.

The development of a blood test for mass screening in the newborn population to detect a variety of inborn errors of amino acid metabolism (Scriver and Clow) led to the founding of the Quebec Network of Genetic Medicine. This network became internationally famous as a model for delivering Genetic Healthcare services to large populations.

A major milestone that recognized Medical Genetics as an important biomedical research discipline in Canada was the formation, in 1972, of the Medical Research Council Medical Genetics Group. MRC groups are established to provide relatively long-term support to interactive scientists who work in areas that MRC considers important to promote. The Principal Investigators were all based at the Montreal Children's Hospital. During successive renewals, the Group expanded to include researchers from the Montreal General Hospital, the Royal Victoria Hospital and the Jewish General Hospital. Currently, under the direction of Rima Rozen and the sponsorship of the Canadian Institutes for Health Research, it has entered its fourth decade of continuous funding.