The karyotype of a neoplasm is known to be associated not only with the histopathologic subtype of the tumor but also with previous cytotoxic exposure and with the geographic place of origin of the patient. Some data also indicate that cytogenetic patterns vary with age and gender. To further investigate whether the frequencies of cancer chromosome aberrations differ between children and adults or between men and women, clinical and karyologic data on 14,141 neoplasms with clonal chromosome changes reported in the literature were assessed. In cytogenetically well-characterized neoplasias, recognized primary and secondary chromosome aberrations were selected, and their frequencies were calculated in men, women, children (< or = 15 years), and adults (> 15 years). In general, the frequencies of the various aberrations did not differ between men and women or between children and adults, but a few exceptions were found. In refractory anemia (RA) and RA with excess of blasts or in transformation, del(5q) was more common among women. In acute lymphoblastic leukemia (ALL-L1 + L2), t(1;19) was more frequently detected in women and del(6q) more common among men. In Philadelphia chromosome positive chronic myeloid leukemia, gain of an extra der(22)t(9;22) occurred more frequently among men. Four primary aberrations were more common in children than in adults: t(8;21) in acute myeloid leukemia (AML-M2), -7 in AML-M4, der(11q) in AML-M5, and t(8;14) in ALL-L3. On the other hand, der(16q) in AML-M4 and t(9;22) in ALL-L1 + L2 were more common in adults. The only secondary cancer chromosome aberration showing a variation with age was loss of the Y chromosome in AML-M2 with t(8;21), being more common in children than in adults. These variations might be spurious and level out when more data are collected, but more probably they reflect, for reasons presently unknown, that different genetic mechanisms may be operative in children and adults--and even in men and women--in the development of some tumors.