system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why did two sexes become necessary for procreation instead of one that handled both aspects?
gpt
genetic diversity. what you suggest is asexual reproduction which many bacteria and some aquatic life here and there do. the issue is that every copy is more or less identical to the first. why is that bad? well, a single disease could now wipe out an entire population. more so no form of reproduction is without glitches here and there and now that bad trait will be copied for every and the species ability to survive decreases.

sexual reproduction ie mixing of two brings in a lot of diversity in the gene pool. yes certainly you can get all the worst traits mixing but you also get a case where all the best ones can mix and you get a super awesome offspring who will go on to likely make more super awesome offspring. that's why sexual selection is such a big thing. they want the best mate to ensure their offspring has best chance of surviving. why mutts ie dogs of unknown breeding are usually much healthier than purebred dogs. they are mixed with everything and are likely to be really hardy and resistant to a lot of stuff.