Scientists Create Human Sperm from Stem Cells
From an evolutionary point of view, the only reason for the male of a species is to create genetic diversity. Parthenogenesis, or reproduction without a male, occurs in several species. The problem is that if something in the environment changes significantly, the species will not be able to evolve in order to adapt to it. However, until that point, it is much more efficient for a species to reproduce without males.
It is an interesting sci-fi type of scenario to ponder.