Why is nondisjunction more common occurrence in older females?

Nondisjunction, the failure of chromosomes to separate properly during cell division, is more common in older females primarily due to the aging of oocytes (egg cells). Women are born with a finite number of eggs, which remain in a dormant state until ovulation, and as they age, the likelihood of errors in chromosome segregation increases. This is linked to the prolonged period of meiOSis that eggs undergo, leading to potential issues with spindle formation and chromosomal alignment. Additionally, age-related changes in the cellular environment may further contribute to the increased risk of nondisjunction in older females.