1 Boisen KA,Kaleva M,Main KM,et al.Difference in prevalence of congenital cryptorchidism in infants between two Nordic countries.Lancet,2004,363:1264-1269. 2 Cortes D,Kjellberg EM,Breddam M,et al.The true incidence of cryptorchidism in Denmark.J Urol,2008,179:314-318. 3 郑新民.睾丸下降和隐睾发生的机制.实用医学进修杂志,2006,34:1-6. 4 Han WK,Kim JH.Hong CH,et al.Structural evidence agains hormonal therapy for cryptorchid testis:abnormal gubernacular attachment.J Urol,2004,171:2427-2429. 5 Kassim NM,Russell DA,Payne AP,et al.Does the cranial suspensory ligament have a role in cryptorchidism? Cells Tissues Organs,2010,191:307-315. 6 Toppari J,Virtanen H,Skakkehaek NE,et al.Envi rorlmeRtaI efrects on hormonalregu]ation of testicuIar descent.Steroid Biochem Mo Biol,2006,102:184-186. 7 Jensen MS,Wilcox AJ,Olsen J,et al.Cryptorchidism and hypospadias in a cohort of 934,538 Danish boys: the role of birth weight,gestational age,body dimensions,and fetal growth.Am J Epidemiol,2012,175:917-925. 8 Marijn M,Brouwers,Leonie M,et al.Risk factors for undescended testis.Journal of Pediatric Urology,2012,8:59-66.