Preface; Unraveling the secrets of sex cells: Martin RH; Frequency and Distribution of Cytogenetic Abnormalities in Human Germ Cells; Frequency and distribution of chromosome abnormalities in human oocytes: Kuliev A, Cieslak J, Verlinsky Y; Frequency and distribution of chromosome abnormalities in human spermatozoa: Templado C, Bosch M, Benet J; Effect of maternal age on the frequency of cytogenetic abnormalities in human oocytes: Pellestor F, Anahory T, Hamamah S; Effect of paternal age on the frequency of cytogenetic abnormalities in human spermatozoa: Buwe A, Guttenbach M, Schmid M; Research on Basic Mechanisms Causing Aneuploidy; Mechanisms of aneuploidy induction in human oogenesis and early embryogenesis: Delhanty JDA; Mechanisms of nondisjunction in human spermatogenesis: Martin RH; Effect of meiotic recombination on the production of aneuploid gametes in humans: Lamb NE, Sherman SL, Hassold TJ; Meiotic spindle checkpoints for assessment of aneuploid oocytes: Steuerwald N; The association of skewed X chromosome inactivation with aneuploidy in humans: Bretherick K, Gair J, Robinson WP; Biological aging and the etiology of aneuploidy: Warburton D; Analysis of Human Germ Cells in Individuals with Somatic Chromosome Abnormality; Segregation of chromosomes in sperm of reciprocal translocation carriers: a review: Benet J, Oliver-Bonet M, Cifuentes P, Templado C, Navarro J; Segregation of chromosomes in sperm of Robertsonian translocation carriers: Roux C, Tripogney C, Morel F, Joanne C, Fellmann F, Clavequin MC, Bresson JL; Sperm studies in heterozygote inversion carriers: a review: Anton E, Blanco J, Egozcue J, Vidal F; Analysis of chromosome segregation during preimplantation genetic diagnosis in both male and female translocation heterozygotes: Munne S; Infertility and Chromosome Abnormalities in Human Gametes; Somatic chromosomal abnormalities in infertile men and women: Mau-Holzmann UA; Meiotic abnormalities in infertile males: Egozcue J, Sarrate Z, Codina-Pascual M, Egozcue S, Oliver-Bonet M, Blanco J, Navarro J, Benet J, Vidal F; Male infertility in reciprocal translocation carriers: the sex body affair: Oliver-Bonet M, Ko E, Martin RH; Chromosome abnormalities in sperm from infertile men with normal somatic karyotypes: oligozoo-spermia: Miharu N; Chromosome abnormalities in sperm from infertile men with normal somatic karyotypes: teratozoo-spermia: Machev N, Gosset P, Viville S; Chromosome abnormalities in sperm from infertile men with normal somatic karyotypes: asthenozoo-spermia: Rives NMD; Chromosome abnormalities in spermatozoa of patients with azoospermia and normal somatic karyotype: Burrello N, Vicari E, Calogero AE; Environmental and Lifestyle Factors; Effect of lifestyle exposures on sperm aneuploidy: Robbins WA, Elashoff DA, Xun L, Jia J, Li N, Wu G, Wei F; Pesticides and the induction of aneuploidy in human sperm: Harkonen K; Mechanisms and chemical induction of aneuploidy in rodent germ cells: Mailhes JB, Marchetti F; Mouse genetic models for aneuploidy induction in germ cells: Eichenlaub-Ritter U; Author Index.