title: Sperm DNA damage: importance in the era of assisted reproduction.
abstract: OBJECTIVE
  With the proliferation of assisted reproductive technologies, there is an increasing awareness of the importance of sperm DNA damage. With the recent advent of in-vitro fertilization/intracytoplasmic sperm injection, we are bypassing the normal natural selection barriers and potentially introducing sperm with damaged DNA. To date, these consequences are still largely unknown.
  
  
  RESULTS
  Infertile men possess substantially more DNA-damaged sperm than fertile men, and this DNA damage may adversely affect reproductive outcomes. There may be a threshold level of DNA damage beyond which embryo development and subsequent pregnancy are impaired. Protamine deficiency and the effect of reactive oxygen species have been implicated in the etiology of sperm DNA damage. Assays of DNA damage are being used clinically to quantify objectively the degree of DNA damage in the sperm of infertile men in the hope of identifying more accurate ways of gauging fertility potential.
  
  
  CONCLUSIONS
  There now exists clinical evidence to show that sperm DNA damage is detrimental to reproductive outcomes. Tests for DNA damage may provide better prognostic information and may allow for better decision-making than standard semen parameters when evaluating the infertile couple. The etiology of the DNA damage and the full extent of the damage on reproductive outcomes need further study.
authors.affiliation: Division of Urology, Department of Surgery, McGill University, and St. Mary's Hospital, 3830 Lacombe Avenue, Montreal, Quebec, Canada. armand.zini@ssss.gouv.qc.ca
authors.forename: Armand
authors.initials: A
authors.lastname: Zini
authors.forename: Jamie
authors.initials: J
authors.lastname: Libman
mesh_terms: D002843:Chromatin / Q000648:ultrastructure; D004249:DNA Damage; D005298:Fertility / Q000502:physiology; D006801:Humans; D007248:Infertility, Male / Q000175:diagnosis / Q000209:etiology / Q000235:genetics*; D008297:Male; D011479:Protamines / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D027724:Reproductive Techniques, Assisted / Q000639:trends*; D013094:Spermatozoa / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D002843:Chromatin; D011479:Protamines; D017382:Reactive Oxygen Species