Five Reasons for Antinatalism

There are in my estimate five rationally-based, axiomatic, ethical, non-self-interested answers to why one should never procreate:

1.) The Negative Utilitarian Argument---
This argument is based on the negative utilitarian grounds that you are preventing the most amount of pain and/or suffering (which is good) while at the same time you are not depriving the potential newborn person of the good (which is not bad). This is the argument argued by David Benatar in his book Better Never to Have Been: The Harm of Coming into Existence (by Oxford University Press) and other philosophers as well. 

This argument goes that good things are good, bad things are bad. If we are to prevent the bad for a new generation (by not having this potential generation) than this is good, because there will be no new person to experience suffering. On the same token, by not procreating a new generation you are not depriving that potential being of good because that potential being never existed to "know" there was good to be deprived of...literally there is no-thing there to be deprived. On a negative utilitarian scale it is win/win as there is no deprivation of good (which is not bad) and also no experience of bad/suffering for a new child (which is good). You have prevented a new potential being from suffering without any side effects (that potential but literally non-existent being is not "deprived" of experiencing the good as nonexistent beings don't get deprived).

To put this more succinctly.. the central pillar of Benatar's asymmetry argument is (BNHB, p. 30):
Pleasure benefits us and pain harms us.
(1) The presence of pain is bad.
(2) The presence of pleasure is good.
So far, pleasure and pain are symmetrical in their goodness and badness. But they are not symmetrical with respect to their absence. More specifically:
(3) The absence of pain is good, even if that good is not enjoyed by anyone, but
(4) The absence of pleasure is not bad unless there is somebody (an actual somebody) who is deprived by its absence.

[Sidenote..even if you live a "charmed" life, the ultimate harm of death befalls everyone..but there is rarely or never such thing as a "charmed" life anyways].

2.) The Eastern, Schopenhauerian, and Ancient Greek Forms of Suffering Argument---
In Eastern philosophy and in some forms of Ancient Greek philosophy there is a notion that suffering simply comes from being deprived. Buddhism goes further and calls this "attachment to desire" in the Second Noble Truth. At least on the "First Noble Truth", that "life is suffering", Buddhism is correct. However, there is no metaphysical/mystical/divine way to get rid of this desire as Buddhism and some Ancient Greek Philosophy schools go on to prescribe; we are always going to be deprived as long as we live. Humans are deprived at almost all moments and this simply causes suffering at almost all moments. We always need food, water, shelter, the basics of life.. Along with this we need entertainments of all sorts (similar to the H.L. Menken quote). We cannot "just be" and be happy at all times. We are in continual need of fulfillment from a deprivation that does not cease. As long as our biological and psychological needs are never fulfilled, we are never truly in a state of pure bliss or happiness, but instead a state of "continual becoming". In Platonic terms we are never a perfect being, but always a shadow being that is moving in time and thus in flux. According to this theory.."enlightenment", "nirvana", "tranquility" or whatever other pinnacles of self-actualization, cannot really be achieved in our time as living beings because de facto, as a rule of life and being thrown into existence, we must always try to fill this constant deprivation... we will always need to overcome our human need to survive, sublimate any feelings of despair, ennui, and entertain ourselves. We may be "temporarily satisfied", but this is never complete. [Sidenote...Callous and unthinking people seem to believe that this deprivation is not a state of humans, but then go on to live exactly the life of deprivation thus described. One can try to deny that which causes suffering while still suffering.]

If bliss is not had (from birth on to death), and suffering exists (deprivation exists)... simply put, this is not a condition that is right to subject another being to.

3.) Argument of Consent and "Rights" Argument---
Simply, this argument states that since it is an impossibility to consult an adult version of the potential child the parent is creating (on whether it would have liked to been born), the parent cannot assume that it is all right to in fact go ahead and throw a new being into the world. Using statistics to claim that the potential person will probably want to be born does not take away the fact that it might not have wanted to be born in the first place. Also, retroactively saying that the new being can commit suicide if it really hates life is cruel. To quote E.M. Cioran "You always kill yourself too late". This is one major reason suicide is not a justification for having a child that possibly would not want to be born. Another reason is that giving a person who did not want to be born an option of suicide is giving it options of choosing between the lesser of harms.. living in a world it did not ask for (harm 1) or doing itself in for good (harm 2). Harm is still enacted by the being who wants to commit suicide even if it was a choice by that particular suicidal person to enact it upon himself. Again, anti-procreation stances are not against maximizing pleasure once one is already born, but it is about minimizing pain for at least the potential new being even if it is too late for us "the already born". By killing oneself one is still experiencing a harm to oneself that could have been avoided by not being born in the first place... Choosing a lesser harm amongst an option of harms is still choosing amongst unwanted and unnecessary harm even if choosing a lesser harm is trying to minimize the damage. 

4.) The Gambling Argument---
Though we experience harm throughout our existence, some humans have more harm in their lives than others. By having children, a parent is always running the risk of having children that will experience lives with much more harm than others. It could be a genetic disorder/disease; it could be a completely traumatic life experience/episode;, it could be a health disorder, mental disorder, or any number of terrible terrible instances and ailments that can befall a human... The parent simply does not know the negative consequences that will befall a new life and by having a child, the parent is taking that risk. Even if likelihood is supposedly "high" for a "happy" "well-adjusted" life.. the fact that there is risk at all and that we are gambling with people's lives is reason not to have children. 

5.) Treating people as Means and not an Ends Argument---
There is an economic and social machine that all societies create. By knowingly throwing another unit of labor into the market(or society in general), you are making a cog in a wheel. The argument would say that the new child is now treated as a cog that was born to serve a collective.. Now, the child was born not for itself, but for some entity (in this case society).. Is the child here to increase technology for no reason except to increase technology? Is it here for its parent's sake? For him/her/future beings/technological innovation/science (insert any outside entity)...? If so, those are all not reasons for the CHILD, the individual, but for other things outside that individual.. if that is the case the child is only here as a means to someone ELSE's ends.. The only reason anyone is put into existence is because of someone else's ends.. The gift of life is for others, not for the gift itself. You cannot give a gift to something that didn't exist in the first place.