Benatar's asymmetry argument for antinatalism is an argument based on the difference between harms and benefits viewed in two scenarios — when the person in question exists and when the person in question never exists.
The argument, introduced by David Benatar in his 2006 book, Better Never to Have Been: The Harm of Coming into Existence, aims to establish that coming into existence is always a harm for the one who's coming into the world.
David Benatar argues that there is a crucial asymmetry between the good and the bad things, such as pleasure and pain: however Regarding procreation, the argument follows that coming into existence generates both good and bad experiences, pain and pleasure, whereas not coming into existence entails neither pain nor pleasure.
Therefore, the ethical choice is weighed in favor of non-procreation.
Benatar explains the main asymmetry using four other asymmetries that he considers quite plausible:[2][4]