Antinatalism is the idea that is it morally wrong to bring new sentient life into being, because of the inevitable suffering it is bound to endure.
One of the main proponents of this view is David Benatar, author of Better Never to Have Been: The Harm of Coming into Existence.
Benatar suggests that there is a fundamental asymmetry between existence and non-existence insofar as they relate to the goodness or badness of pain and pleasure. Specifically, he suggests that it is good that non-existent beings don’t experience pain, but it is not bad that they don’t experience pleasure. As such, there is only virtue in non-existence, and so it’s better not to create conscious beings.
However, the obvious fallacy here is that in the case of non-existence, neither badness nor goodness accrue to anyone, since there is no one around for them to accrue to.
In order to form such an opinion, Benatar seems to shift between a subjective, personal view of the world, and an objective, nihilistic one. When talking about the potential pleasure of sentient beings, Benatar takes a cosmic, and therefore appropriately nihilistic viewpoint, since so far as the universe is concerned (independent of conscious minds), there is no difference whether anyone is around to experience pleasure or not. However, when talking about the potential for suffering, Benatar shifts to the viewpoint of subjective experience, and notices that it would be better not to suffer for a being who already exists.
In order to be consistent, we should keep the same viewpoint and notice that as far as the universe is concerned, it is equally unimportant whether there are beings around to experience suffering or pleasure. Cosmic nihilism renders both situations equally meaningless.
On the other hand, both pleasure and pain can only accrue to a sentient being who can experience them, and therefore already exists.
As such, whether or not it is “better never to have been” depends fully upon the actual experience of the individual, and therefore whether or not they deem it so. Life is thus an opportunity to make it worth the trouble.