Primordial germ cells are derived from:

Formation of primordial germ cellsStructures derived from neural crest are neurons of spinal posterior (dorsal) nerve root ganglia, neurons of sensory ganglia of the 5 to 10th cranial nerves, neurons and satellite cells of sympathetic ganglia etc.In the region where testes is to develop, the germinal epithelium gets thickened and is known as genital ridge.The cells of germinal epithelium proliferate and forms sex cords which gets conveed into medullary cords and finally gets canalized to form seminiferous tubulesChorion is formed by the parital/ somatopleuric extraembryonic mesoderm (on the inside) and the overlying TrophoblastThe cells of the ovaries and the testes, from which germ cells are formed, are believed to be segregated early in the life of the embryo.