Underwriting rare diseases in life insurance presents unique challenges due to limited data and the complex nature of these conditions. Rare diseases often exhibit diverse progression patterns and uncertain prognosis, complicating traditional risk assessment. Gathering and evaluating medical information becomes critical when conventional data sources like large epidemiological studies or extensive portfolio experience are lacking. Advances in genetic testing, precision medicine, and novel therapies not only further complicate underwriting but also offer opportunities for insurability. Navigating these complexities requires balancing scientific rigor with ethical considerations and expert judgment. These issues, practical solutions for underwriting rare diseases, and the dedicated role of the Chief Medical Officer are explored comprehensively here, emphasizing the need for fair decision-making in this evolving field of medical underwriting.