Genetic diseases have been thought to be acquired as a result of sheer bad luck. However, recent advances in medical science have demonstrated the mechanisms of genetic disorders, which enable us to intervene with their occurrence and treatment. Today, gene therapy, once considered too risky, has become safer and can save the lives of patients with previously untreatable and lethal genetic diseases. However, the positive expectations from gene therapy are overshadowed by their extremely high prices. Thus, the duty of society in the provision of gene therapies has been frequently discussed. The discussions mainly focus on how to meet the genetic treatment needs of patients without violating the notion of justice and fairness in society. This study discusses the theoretical grounds for society's duty to compensate for genetic disease patients' disadvantages by providing them with appropriate genetic treatment. The main question is whether a fair and just system requires society to provide available lifesaving gene therapy to patients in need. The discussion is constructed on the crucial notion of the fair equal opportunity principle in a just system and the plausibility of including disadvantages emerging from bad luck in the natural lottery in the domain of justice.