Abstract: Methods are provided for the generation of male germ cells from somatic cells. Included are methods of non-integrative reprogramming for germ cell differentiation with a reduced risk of neoplasia during in vivo differentiation by the inclusion of VASA with the reprogramming factors. Also included are methods of generating male germ cells from reprogrammed pluripotent cells by direct injection of the reprogrammed cells into the seminiferous tubules. In some embodiments the somatic cells are derived from a male with oligospermia or azoospermia, which may be the result of a genetic abnormality in Azoospermia Factor (AZF) region.