Is Human Reproduction Un-Ethical?

[Brometheus]

Hear me out.

1. If no God or after-life exists;
   
2. There is no other point to being, than what we make of our lives here; 
   
3. And, if some children will find in this life great fulfillment, while others find incredible pain and suffering- which we cannot possibly foreknow; 
   
4. To wager that a child will enjoy life, to a degree greater than the sum of the pain and suffering;
   
5. Which is to wager with somebody elses life, potentially exposing another human being to immense grief and pain;
   
6. Which is needless, considering the fact that their is no reason for us to be, or to continue to exist;
   
7. And, that the, act of having children is not necessary for any purpose other than our own gratification; 
   
8. Thus, having children is a selfish, greedy act which can impose great pain on another human being;
   
9. Having children is thus un-ehtical and immoral. 
   

What do you think? 

You could plug literally anything into that argument to replace reproduction and get to the outcome unchanged. It makes the argument effectively worthless.

Besides, one could easily argue that it is the contributing factors that cause pain and suffering that are immoral, not the act of reproduction; after all, as you've already established, being born can either lead to happiness or suffering, dependent on outside factors. Is it not then the fault of those additional factors? After all, if they were removed, then the child would have no chance to suffer, and his birth would be a moral act.

But what is the point of continuing the human-species? Their contributions, if any, benefit only to themselves, but they themselves do not need to exist for anything. Nobody would miss us if we were all extinct. If we arose by chance and are here for nothing, this is the total sum of all that any of us can contribute, in the large scheme of things.

This is what bothers me most.