Effect of paternal age on human sperm chromosomes

Objective: To investigate whether increased age alters the frequency and type of chromosomal anomalies in human spermatozoa. Design: Semen specimens were collected from donors via masturbation; cytogenetic studies were performed on sperm chromosomes after heterologous (human-hamster) in vitro fertilization. Setting: Cytogenetics Laboratory, Genetics Department, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Brazil. Patients(s): Seven men ages 59-74 (older group) and five men ages 23-39 (control group). Main Outcome Measure(s): Frequency and types of chromosomal anomalies in older and control group donors. Result(s): The frequency of numerical and structural aberrations (acentric fragments and complex radial figures) was significantly greater in chromosomes of older donors when compared with those of the control group. Conclusion(s): The higher frequency of sperm chromosome aberrations in older men was mainly a result of increased nondisjunction, acentric fragments, and complex radial figures. (Fertil Steril (R) 2001;76:1119-23. (C) 2001 by American Society for Reproductive Medicine.).