Exposures before or after brain development have a lower probability of damage to the brain. Thus, there are very sensitive windows during pregnancy with a higher degree of exposure vunerability than other periods of development. Reproductive Tract Development in the Fetus Males Genital differentiation of the fetus is dependent on the effects of androgenic hormones. Normal development of the male fetus includes the proliferation of Wolffian ducts, the closing of the urogenital sinus, scrotal swelling and penile development. Compounds with androgenic effects will promote such development even in the absence of androgens.
Hormonal production is regulated by enzymes.
If the enzyme aromatase is absent in female fetal ovaries, pseudohermaphrodism can be observed where both male and female systems are partially present. 5-alpha reductase is another critical enzyme, responsible for the formation of testosterone. When the actions of steroid enzymes are inhibited, imbalances in testosterone and estradiol levels result. The molecule has a tremendous estrogenic capability, more potent than most pesticides. DES was the first synthetic steroid estrogen produced, and was originally used to prevent miscarriages in pregnant women.