The effects of aging, gender and lifestyle factors on inducing chromosomal damage (micronuclei) and nuclear degenerative changes were assessed using the micronucleus test on exfoliated cells of the oral mucosa. The sample included 80 healthy subjects divided into four groups according to age and gender: men and women aged 19-29 years (M19, W19) and men and women aged over sixty years (M60, W60). An interview questionnaire was used to characterize the sample and to determine an index reflecting lifestyle (HLI). The frequency of micronuclei and nuclear degenerative changes was significantly higher among the elderly ( p<0.001) and did not differ by gender among young people ( p>0.05). The occurrence of micronuclei was similar among elderly men and women ( p>0.10), but karyorrhexis and karyolysis were more frequent among men ( p<0.005 and p<0.025, respectively), who also had a lower HLI than the other groups ( p<0.0004). The results of the study indicate that age is the main factor associated with the induction of genetic material damage.