Yes, it could. Two philosophers who have written in this vein are Seana Shiffrin and David Benatar. You can find at quick introduction to this debate (along with additional literature) at http://theviewfromhell.blogspot.com.au/2008/08/is-coming-into-existence-agent-neutral.html .

Well, with the symmetrical argument you could conclude the opposite: If causing happiness is good and if life is in part happiness, then procreating is good. Both conclusions seem inadequately supported. It matters how much suffering and how much happiness one's offspring is likely to face. And there are other valuable and disvaluable things besides happiness and suffering: knowledge, culture, art, science, sports and love may all be good things a future person will experience -- good even if they are unaccompanied by happiness. And there are also contributions this future person will make to the lives of others -- good and bad contributions. So the question whether it's bad to procreate requires a more complex weighing up of considerations than is suggested by your argument.

I used exactly this example in an essay published over 20 years ago as one of the arguments in support of a more subtle interpretation that had been first proposed by Tim Scanlon. On this reading, it is the permission one is claiming for oneself that is to be universalized. So instead of asking whether one can will that all people act on one's maxim of remaining childless, one is to ask instead whether one can will that all people be permitted to remain childless. In the world as it is, we can certainly will this universal permission (because enough others would decide to conceive even without a duty to do so), and therefore each of us is permitted to act on the maxim in question.

Funny you should ask -- there's a doctoral dissertation now being written on exactly this question (I am marginally involved in its supervision). The student essentially argues for the conclusion you suggest, claiming that, in the world as it is, those who decide to have children at all ought to adopt rather than conceive. Adoption confers a huge benefit on a child who would otherwise grow up under conditions of institutionalization and deprivation (for example, in an ophanage in Cambodia or Niger). And adoption does not take away a benefit from anyone: the person one would have conceived will simply never exist. There's no stance of the academic community on this issue, yet. Time will tell whether the student's view will be widely accepted or rejected. It's bound to stimulate discussion if only because most affluent people believe that they have every right -- not just legally, but also morally -- to conceive if they wish. The student's thesis might be opposed on behalf of the people who, if...

Isn't the reason just this? When an adult dies prematurely -- say at age 40 -- then she is losing many years of valuable life. When a child dies, then she is losing those same valuable years above 40 and in addition all the good life years up to 40. So the basic thought here is simply that the earlier someone dies, the greater the loss. While the common view seems to me to be based on this thought, it is not unassailable. You might say that the loss of years above 40 isn't a serious loss for someone dying as a small child, who has no conception of what such years would be like and moreover is very different from the mature adult she would have become 40 years hence. Thinking this through further, you might reach the view that the worst age at which a human being could die is in her or his mid-20s. At that age, one has a conception of the life one wants to lead and also typically is a productive member of one's family and society. Such a death is a great loss to the person and to many others...

How about sending them Jostein Gaarder's Sophie's World ? It's been very popular and very effective in the sense you intend.