Changes

* Sex cord cells proliferate to form the testes cord.  During this period '''SRY''' is expressed for the first time within '''Sertoli cells''' (SRY is NOT expressed in primordial germ cells).

* Sex cord cells proliferate to form the testes cord.  During this period '''SRY''' is expressed for the first time within '''Sertoli cells''' (SRY is NOT expressed in primordial germ cells).

* Sex cords with a basement membrane become '''semniferous Cords''' which give rise to '''semniferous Tubules'''.

* Sex cords with a basement membrane become '''semniferous cords''' which give rise to '''semniferous tubules'''.

* '''Within the semniferous cords''' are two cell populations:

* '''Within the semniferous cords''' are two cell populations:

** '''Primordial germ cells'''  - Prospermatogonia which give rise to '''spermatozoa'''

** '''Primordial germ cells'''  - Prospermatogonia which give rise to '''spermatozoa'''

* '''Between cords''', the loose mesenchyme undergoes '''vascularisation''' and develops as '''stromal tissue'''.

* '''Between cords''', the loose mesenchyme undergoes '''vascularisation''' and develops as '''stromal tissue'''.

* Within the stromal tissue, cells condense into clusters to form specialized endocrine units - the interstitial '''Leydig's  cells'''

* Within the stromal tissue, cells condense into clusters to form specialized endocrine units - the interstitial '''Leydig's  cells'''

== Female ==

== Female ==