Development of Reproductive system in Fetus; Genetic, endocrine and environmental factors - Research Proposal Example

The primordial germ cells migrate to these ridges from the primitive yolk sac at this stage (Bullough and Bullough, 185). During the sixth week of gestation period the gonads begin to develop into testes in case of male fetus or transform into ovaries after waiting for some more weeks in case of female fetus (Bullough and Bullough, 185). This development of fetus reproductive system either to form testes or to form ovaries is controlled by the genetic factors established during fertilization. If the cells of the embryonic body contain the TDF gene usually carried by Y chromosome then the gonadal ridges form the seminiferous tubules and related ducts which later develop to secrete testosterone for the development of male reproductive system.

In the absence of TDF genes the gonads wait until the twelfth week to begin to develop into female reproductive organs. This inherent tendency of growing into female reproductive system is known as Eve plan (Bullough and Bullough, 185). The primitive eggs present in the female fetus begin meiosis until they reach the “prophase arrest stage” and remain inactive until puberty. With the development of permanent kidneys the ovaries or testes come out of the thoracic abdominal cavity and take their final position in the pelvic cavity (Bullough and Bullough, 185).

The fetal growth is a process controlled by several factors including genetic makeup of the fetus, the success of the implantation process, the availability of nutrients and oxygen to the fetus, hypoxia, cigarette smoking, infection, maternal nutrition, and a variety of growth factors, cytokines, and proteins of maternal and fetal or placental origin (Giudice, 307). Among the genetic factors IGF gene is also found to have considerable importance in fetal growth. Studies on human fetus showed that the natural deletion of exon 4 and 5 from IGF-I gene can cause huge restrictions in the physical and mental development