The growth of the testes during the fetal period

OBJECTIVE: To determine the size and position of the fetal testes during gestation. MATERIALS AND METHODS: The study comprised 48 testes obtained from 24 human fetuses with no congenital abnormalities, aged 14-40 weeks. The development of the fetuses was evaluated by measuring the crown-rump length. Testicular size was assessed as the height, width, thickness and weight, and the position of testes determined during fetal development. RESULTS: The testes in 11 fetuses (22 testes) aged 14-37 weeks were in the abdominal cavity; no testis had descended to the scrotum in any fetus until 27 weeks of gestation. Both testes had descended to the scrotum only in fetuses aged 33-40 weeks. There was no significant difference between right and left testicular size in 13 fetuses (26 testes) aged 27-40 weeks, but size correlated with gestational age (P<0.001). CONCLUSION: All testes had descended to the scrotum by 33 weeks of gestation, but there was considerable variation in position from 27 weeks.