As in the female, the initial stages of development begin in the fifth week with development of the mesoderm forming the gonadal ridge.

 
  • 第4周,卵黄囊顶近尿囊处的内胚层出现称原始生殖细胞。第5周,生殖腺的体腔上皮细胞向深层增生成初级性索。
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