Germ cells will become eggs or sperms, as result of a prolonged process of division and differentiation, compartmentalized in time and space. The exposure of the organisms to mutagens can affect this process, modifying the type and proportion of gametes produced, damaging their integrity and their ability to contribute to the formation of the next generation. This contribution is not similar for both parents and that is why in this study we compared the effect of the mutagen Methyl-Methanesulphonate (MMS) in the germ cells from female and male of D. melanogaster through the ability of germ cells to produce progeny and, by using markers linked to X, was determined the distance between the white-miniature genes from classic mapping to assess the type and proportion of gametes produced that contribute to the next generation. Wild-type females w+m+/w+m+ were mated with hemizygous males wm/Y of D. melanogaster to obtain F1 larvae of 72±4h that were fed food enriched with successive dilutions of MMS (0.24 µM - 1mM) or distilled water (negative control), so that the maturation of germ cells occur in the presence of the mutagen. Survival (S) of treated flies was compared to the negative control. Of flies recovered of treatment 50 virgins ♀♀ (T) and 50 ♂♂ males (T) were selected for each concentration and were mated individually with untreated flies (NT) as follows: T X T, T X NT and NT X T. The progeny was classified and counted by phenotype to calculate fertility, average amount of progeny and recombination frequency. Higher concentrations of MMS were lethal. The Fertility and amount of progeny decreased in the crosses: T XT y NT XT. The frequency of recombination between the w-m genes in the progeny of exposed individuals were modified in certain concentrations depending on the parent exposure (female or male). The progeny more affected was from T X T crosses (both exposed) but when only one parent was treated, the germ cells from F1 males exposed were more affected than the germ cells of F1 females treated. Probably the treatment with MMS interfered with the process of maturation of the germ cells or even, one part of the germinal cells of the parent treated were eliminated without contribute in the formation of the new individuals. Acknowledgements: Postgraduate in Biological Sciences-UNAM, CONACyT Grant. To Drosophila Stock Center Mexico by provide the biological material, and to M. en C. Yaneli Trujillo-Varela by technical support.