Fatal degenerative brain diseases, such as Parkinson's and Alzheimer's, are influenced by age-related neuron loss, particularly dopaminergic neurons, which declines by about 13% per decade after age 45. While most individuals may not reach the critical neuron loss threshold that triggers symptoms of Parkinson's disease, the risk increases with extended lifespan. Cloning as a means to extend life raises questions about the inevitability of encountering degenerative processes, which can lead to suffering but not necessarily death. Genetic factors play a significant role in the development of these diseases, with some forms being heritable. Ultimately, while degenerative diseases can severely impact quality of life, they do not uniformly lead to fatal outcomes.