When does the testis of a male fetus fully develop?

Under normal circumstances, the testes of male fetuses are mostly fully developed by around the 7th to 8th month of pregnancy, forming the foundation for subsequent normal function. If development is delayed or abnormal, longer observation or medical evaluation may be required. In case of concerns, it is recommended to seek medical consultation early. Detailed analysis is as follows:

If prenatal examinations show normal fetal development without chromosomal abnormalities or reproductive system defects, the testes of male fetuses complete structural differentiation before the 7th month of gestation, including the formation of key tissues such as seminiferous tubules and interstitial cells. By the 7th to 8th month of pregnancy, the size, shape, and internal structure of the testes are essentially complete. The testes gradually descend into the scrotum, preparing for functional development after birth.

If prenatal ultrasound reveals delayed testicular development in a male fetus—for example, if complete structures are not observed after the 8th month of pregnancy, or if cryptorchidism (undescended testes) or abnormally small testes are present—this may indicate hormonal imbalances, chromosomal abnormalities, or congenital malformations of the reproductive system. In such cases, further diagnostic tests such as hormone assays and genetic testing are needed to determine the underlying cause. Some cases may require medical intervention after birth to support further testicular development or functional recovery.

Regular ultrasound examinations during pregnancy are essential to monitor the development of the fetal reproductive system. If abnormal testicular development is detected in a male fetus, follow the doctor's recommendations to complete relevant evaluations and avoid delays in timely intervention. After birth, continued monitoring of testicular position and development is important, and any abnormalities should prompt immediate medical attention.