Telomeres appear to function as an endogenous timing mechanism in human beings. Telomere attrition not only provides a satisfactory explanation for some aspects of aging, it might also resolve enigmatic features of complex genetic traits that are age-dependent. If, with the passage of time, telomere attrition in human beings leads to genomic instability and particularly the loss of chromosomes, then the age dependency of phenotypic expressions of complex genetic traits might result from the temporal loss of heterozygosity and the consequent expression of disease-causing genes. In this way, telomere attrition might play a role not only in aging, but also in the diverse expression of complex genetic traits, such as essential hypertension, non-insulin-dependent diabetes mellitus, atherosclerosis, and cancer.