Answer

So this time, exceptionally, you want me to write דווקא my own opinion.
It is not an altruistic act, because there is no contribution here from you to someone else. The child himself would not have been in the world had you not brought him into it. And as for the world in general, it is doubtful that this contributes anything.
It is also not necessarily selfish. It depends on why you are bringing the child into the world. If it is because of the commandment, then there is no selfishness here (and perhaps there is some kind of spiritual rectification in the world).
It may be that you meant to ask about raising the child, not about bringing him into the world. Here there is already a beneficiary, and that can be altruistic. But it seems to me that here too the answer is not clear. It depends on why you are raising him. Even if it is done only for his sake, you have a responsibility to do so, because you are the one who brought him into the world.