research Decreased Fertility in Male Rats Administered the 5α-Reductase Inhibitor, Finasteride, Due to Deficits in Copulatory Plug Formation 37 citations, January 1991 in “Reproductive Toxicology” Finasteride reduces male rat fertility by causing issues with copulatory plug formation.
research Reversible Decreases of Fertility in Male Sprague-Dawley Rats Treated Orally with Finasteride, a 5α-Reductase Inhibitor 28 citations, January 1991 in “Reproductive Toxicology” Finasteride temporarily lowers male rat fertility without affecting libido.