Given that humanity isn't exactly lacking in the reproductive arena, I'm ambivalent about it from a moral perspective.
If we were close to extinction tho, say from a horrible plague or a la Battlestar Galactica (LOL), I'd have a different opinion.
So, what sways my opinion is more to do with 'quality vs. quantity' of life.
I'm very pro-quality. I'd rather have 1 or 2 well-brought up, productive members of society than a pack of poorly raised societal parasites with little sense of social responsibility.