Final answer:
The testes must descend in a male infant to ensure a proper temperature for sperm viability and motility. The presence of testosterone during fetal development directs the differentiation of the bipotential gonads into male sexual organs. If the testes remain inside the body, increased temperatures can lead to reduced fertility or infertility.
Step-by-step explanation:
The student asked about the rationale for ensuring that the testes have descended in a male infant. The descent of the testes is critical because sperm require a temperature about 2°C lower than the normal body temperature for viability and motility.
During fetal development, the testes should move down from the abdomen into the scrotum, which is an external pouch below the pe nis. This process is pivotal for fertility; if the testes do not descend properly, a condition known as cryptorchidism, it can lead to reduced fertility or infertility due to the higher internal body temperature.
In males, the presence of testosterone is pivotal for the development of male sexual organs from the primitive gonads, which are bipotential and can develop into either male or female reproductive organs depending on hormonal influence.
Tissues that produce the pe nis and scrotum in males produce the c litoris and labia in females, respectively. Thus, male and female anatomies are the result of a divergence in the development of what starts as common embryonic structures.
For successful reproduction, parental endocrine systems must secrete the appropriate hormones to induce the production and release of gametes.
Reproductive behavior must also facilitate the transfer of male gametes, or sperm, which are immobile at body temperature and therefore require the cooler temperature provided by the scrotum to become motile.