Multiple studies have found that micronuclei frequency in women is higher than in men and that the number of micronuclei increase until around 70 years of age. Micronuclei levels ranged from 0.5 to 1.4% in men to 0.9 to 1.8% in women. Gender-related differences were mainly seen in younger age groups (<= 50 years) with an almost two-fold difference between men and women. The patterns in the number of micronuclei after 70 years of age is controversial. Some studies have shown that in individuals over 70 years of age, micronucleus frequency increases in both sexes. On the other hand, other studies have found that in the oldest age groups, micronuclei frequencies level off. The deficiency of micronuclei in some of the oldest age groups may be explained by the fact that micro nucleated cells are preferentially eliminated by apoptosis. However, higher micronuclei frequency corresponds to a decreased efficiency of DNA repair and increased genomic instability, which are typical in older subjects. Age-related increases in micronuclei frequency also correspond well with age-related increases in the hypoploidy and the age-related increase in sex chromosome loss. Alternatively, the leveling off of frequency of micronuclei in older subjects would suggest a threshold of genomic instability that cannot be crossed if the person is to survive. If this were the case, women appear to reach this threshold faster than men.