Skip to main content Accessibility help
  • Print publication year: 2021
  • Online publication date: March 2021

Chapter 1 - Development of Reproductive Systems at the Embryo Stage

from Section 1 - Physiology of Reproduction


The female and male reproductive tracts originate from the same embryonic/fetal tissue. The gonads and internal and external genitalia begin as bipotential tissues. The indifferent gonad consists of a medulla and cortex. Human female and male embryos develop in the same way for the first 6 weeks, regardless of genetic sex (46,XX or 46,XY karyotype) (Figure 1.1). The one way to tell the difference between 46,XX and 46,XY embryos during this time period is by looking for a Barr body (“inactive” one X chromosome) or a Y chromosome. The medulla of the XY embryo will develop into the testes and the cortex will regress. In the XX embryo, the ovary will originate from the cortex and the medulla will decline. A complete 46,XX chromosomal complement is necessary for normal ovarian development. The second X chromosome contains elements essential for ovarian development.

Related content

Powered by UNSILO
1.Eddy, EM, Clark, JM, Gong, D, Fenderson, BA. Origin and migration of primordial germ cells in mammals. Gamete Res. 1981; 4:333362.
2.Konishi, I, Fujii, S, Okamura, H, Parmley, T, Mori, T. Development of interstitial cells and ovigerous cords in the human fetal ovary: an ultrastructural study. J. Anat. 1986; 148:121135.
3.Francavilla, S, Cordeschi, G, Properzi, G, et al. Ultrastructure of fetal human gonad before sexual differentiation and during early testicular and ovarian development. J. Submicrosc. Cytol. Pathol. 1990; 22:389400.
4.Ulloa-Montoya, F, Kidder, BL, Pauwelyn, KA, et al. Comparative transcriptome analysis of embryonic and adult stem cells with extended and limited differentiation capacity. Genome Biol. 2007; 8:R163.
5.Eguizabal, C, Shovlin, TC, Durcova-Hills, G, Surani, A, McLaren, A. Generation of primordial germ cells from pluripotent stem cells. Differentiation 2009; 78:116123.
6.Baker, TG. A quantitative and cytological study of germ cells in human ovaries. Proc. R. Soc. Lond. B. Biol Sci. 1963; 158:417433.
7.Li, Y, Zheng, M, Lau, YF. The sex-determining factors SRY and SOX9 regulate similar target genes and promote testis cord formation during testicular differentiation. Cell Rep. 2014; 8:723733.
8.Hannema, SE, Hughes, IA. Regulation of Wolffian duct development. Horm. Res. 2007; 67:142151.