Changes

In the female '''alpha-fetoprotein''' binds to estradiol which has been secreted by the fetal ovary. This binding results in the complex being unable to cross the [[Blood_Brain_Barrier_-_Anatomy_%26_Physiology|blood brain barrier]]. This mechanism protects the female brain from the masculinising effects of estradiol and allows the development of a 'feminising' '''surge centre''' at the point of the rostral part of the [[Midbrain_-_Anatomy_%26_Physiology|mesencephalon]].

In the female '''alpha-fetoprotein''' binds to estradiol which has been secreted by the fetal ovary. This binding results in the complex being unable to cross the [[Blood_Brain_Barrier_-_Anatomy_%26_Physiology|blood brain barrier]]. This mechanism protects the female brain from the masculinising effects of estradiol and allows the development of a 'feminising' '''surge centre''' at the point of the rostral part of the [[Midbrain_-_Anatomy_%26_Physiology|mesencephalon]].

==Normal Sexual Development==

==Normal Sexual Development==

Throughout normal sexual development there are series of defined phases;  

The development of the reproductive system develops in close proximity and concurrently to the renal system. Throughout normal sexual development there are series of defined phases;  

===Pregonadal Phase===

===Pregonadal Phase===

The pregonadal phase represents the stage where '''germ cells''' begin to migrate from the yolk sac of the developing embryo. Primitive primordial germ cells are formed in the yolk sac (the yolk sac is part of the digestive system in the embryo). These primitive germ cells migrate from the yolk sac through the mesentry to the '''genital ridges''' which are small elongated pieces of tissue beneath the peritoneum situated at the dorsal aspect of the abdominal cavity. These germ cells then begin to divide by mitosis and the gonads are developed from these genital ridges.

The pregonadal phase represents the stage where '''germ cells''' begin to migrate from the yolk sac of the developing embryo. Primitive primordial germ cells are formed in the yolk sac (the yolk sac is part of the digestive system in the embryo). These primitive germ cells migrate from the yolk sac through the mesentry to the '''genital ridges''' which are small elongated pieces of tissue beneath the peritoneum situated at the dorsal aspect of the abdominal cavity. These germ cells then begin to divide by mitosis and the gonads are developed from these genital ridges.