Genetic Diseases are very common.

=> Approximately 6 out of 10 people will be affected by a condition which has some genetic background. Genetic conditions can range from mild to very severe.

Cystic Fibrosis is a chronic, genetic condition that causes patients to produce thick and sticky mucus, inhibiting their respiratory, digestive, and reproductive systems. Like Thalassemia, the disease is commonly inherited at a 25 percent rate when both parents have the Cystic Fibrosis gene.

you did not attach the discourse, but i assume it to be the discourse on the origin and basis of inequality among men (the original titile in french is: "discours sur l'origine et les fondements de l'inégalité parmi les hommes"), also know as "second discourse". in this discourse, jean-jacques rousseau emphasizes that private property is the basis of all inequalities.

therefore, what enabled the old regime to maintain as long as it did was private property.