External Genitalia Abnormalities in Male Rats Exposed In Utero to Finasteride, a 5α-Reductase Inhibitor
 July 1990   
in “
 Teratology 
”
 
      
   TLDR  Finasteride exposure in pregnancy causes genital abnormalities in male rats.   
  The study investigated the effects of in utero exposure to finasteride, a 5α-reductase inhibitor, on male rats. The results showed that exposure to finasteride caused external genitalia abnormalities, including hypospadias and decreased anogenital distance. The study suggests that exposure of women of childbearing potential to even low levels of finasteride should be avoided due to the risk of inducing hypospadias in male offspring. The study also highlights the role of DHT in the growth of the perineal region in males.
    
  