Chromosomal abnormalities in sperm.

The use of FISH (fluorescent in situ hybridization) in decondensed sperm nuclei has allowed, during the last decade, to indirectly study the chromosome constitution of human spermatozoa. Studies in control populations have been used to set up the basal level of aneuploidy for all human chromosomes and, based on conservative estimates, the percentage of chromosomally abnormal sperm in the general population could be considered to be at least 6.7%. In carriers of sex chromosome numerical anomalies and in severe oligozoospermic males (both frequent candidates for intracytoplasmic sperm injection), in structural chromosome carriers (enrolled in preimplantation genetic diagnosis programs) and in couples with recurrent miscarriage, sperm chromosome analyses by FISH could help to better establish a reproductive prognosis.