From fish to mammals, oogenesis has evolved to produce fewer oocytes of the best quality, from approximately millions to a few or one in humans. However, vertebrates from fish to mammals produce an enormous number of sperm. This point of view proposes that because evolution is a continuous process, someday in the future, spermatogenesis will evolve similarly to oogenesis: fewer sperm of the best quality will be produced.
Vikas Kumar Roy (Wed,) studied this question.