The hormone-dependent events that occur throughout the first wave of spermatogenesis, such as the establishment of the number of Sertoli cells (SCs) and spermatogonial stem cells (SSCs) within the seminiferous cords and the setting up of the blood-testis barrier, are important for adult male fertility. Any changes in the T/DHT ratio can result in male subfertility or even infertility. In this study we aimed to evaluate effects of paternal exposure to 5-alpha reductase type 2 inhibitor, finasteride on litter size, androgen levels and germ cell apoptosis in male offspring during postnatal development.