<prompt> Where do primordial germ cells initially developIn the gonads at week 4 of embryonic developmentIn the yolk sac at week 4 of embryonic developmentIn the gonads at month 5 of embryonic developmentIn the yolk sac at month 5 of embryonic development  <response>: Primordial germ cells, the predecessors to gametes, are first seen in the wall of the yolk sac at week 4 of embryonic development They migrate into the gonads at week 6. 