I hope you mean from an evolutionary perspective, not an atheist perspective, as now pretty much all representatives of major religions have admitted in public debate evolution is a fact of life. So, most theists have moved to a deist position to keep their religion afloat in the face of relentless discoveries and new normalizations of reason.
Progress of a kind, in the words of Christopher Hitchens.
Two genders of most species (not all) are necessary for a species to push the boundaries of its evolution, as the unique sequencing of a tiny part of differential DNA (in combination with DNA changes during life) is responsible for the minute but crucial adaptations to an ever-changing environment. A reason why the value of differences is way more important than the value of commonalities, despite our inverse emphasis.
Without the innate merit of our differences, a species would not evolve and adapt to a changing equilibrium with nature, it depends on for survival.