I've come to the conclusion that while many lives are worth living, no life is worth creating if that life will involve more stress than the very basic amount necessary for a functioning nervous system. I won't go into detail but I believe happiness and suffering are asymmetrical in value for at least two reasons. Suffering is qualitatively worse than happiness is good, it is better not to suffer than it is good to experience happiness. Also, the absence of suffering is good whereas the absence of pleasure/happiness is only bad if an organism has a desire to experience pleasure/happiness. Since an aversion to suffering is a negative desire, causing someone to suffer is bad even if they don't have a conscious desire to avoid suffering (and sperm/egg cells are fortunate not to suffer even if they don't consciously realize how fortunate this makes them). I still say that many lives are worth living because the pleasure and happiness we experience in life helps to mitigate our suffering but again, the opportunity for pleasure and happiness is only worth fullfiling if one has a desire for pleasure/happiness, it's beneficial to avoid suffering even if one does not have a desire to avoid suffering.
There are at least 4 reasons why I will not procreate
1) Ecological. There's no point in reducing one's carbon footprint if you're just going to create more carbon 'feet' altogether. Climate change will be the result of many famines, floods, tsunami's, poor crops etc. and these things will cause great suffering.
2) There are so many existing children who could benefit from the resources I would be willing to spend on a not yet existing child I would create. If not adopted children then I could even use all the money that would have gone into diapers, college education, clothes etc. and donate it to a children's charity.
3) This is not the kind of society I would want to bring my children into. They will spend most of their lives working at a job they find tedious and boring and most people underestimate how much of a bad thing this is. Half the products they consume will be linked to sweat shops, tortured monkeys or some kind of amoral, capitalist activity. People are mean at worst and insensitive at best, sooner or later they will be mistreated or victimized.
4) Even in my ideal anarcho communist society where everyone was loving and compassionate, they would suffer for some natural reason if not from interactions with unsympathetic, fellow humans. Whether it's chronic insomnia, the flu, an anxiety disorder etc., something will cause them to suffer.
I would consider reproducing if climatologists unanimously agreed that global warming was a hoax, every orphan on the planet was adopted and poverty was eliminated, capitalism and statism were abolished tomorrow and every human on the planet became a dedicated empath and if science somehow came up with a means to eliminate all unnecessary suffering, maybe some kind of shot soon after birth or a magic pill or something.