title: Cryptorchidism: classification, prevalence and long-term consequences.
abstract: Undescended testis is a common finding in boys, and the majority of cases have no discernible aetiology. There are unexplained geographical differences and temporal trends in its prevalence. Cryptorchidism, especially bilateral, is associated with impaired spermatogenesis and endocrine function and increases the risk of testicular cancer. There is an urgent need to identify factors that adversely affect testicular development and optimize treatment.
  
  
  CONCLUSIONS
  Cryptorchidism may reflect a primary testicular maldevelopment with long-term consequences.
authors.affiliation: Department of Physiology, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland.
authors.forename: Helena E
authors.initials: HE
authors.lastname: Virtanen
authors.forename: Robert
authors.initials: R
authors.lastname: Bjerknes
authors.forename: Dina
authors.initials: D
authors.lastname: Cortes
authors.forename: Niels
authors.initials: N
authors.lastname: Jørgensen
authors.forename: Ewa
authors.initials: E
authors.lastname: Rajpert-De Meyts
authors.forename: Arni V
authors.initials: AV
authors.lastname: Thorsson
authors.forename: Jørgen
authors.initials: J
authors.lastname: Thorup
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Main
mesh_terms: D000818:Animals; D002648:Child; D015897:Comorbidity; D003456:Cryptorchidism / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012661:Semen; D013736:Testicular Neoplasms / Q000453:epidemiology