I refrain from taking pictures of other people's children (all children are other people's to me) even though I would like to, and on the rare occasions I do take pictures of children, I refrain from posting them on this blog because I assume (1) you shouldn't do that without asking the child's parents and (2) asking the child's parents is such a weird unpleasant thing to do, opening up as it does the possibility of discussion re: the various uses unsavoury people might have for such pictures, so it's just not worth the effort.
Presumably this is why the internet is so full of cat pictures (of course, I am trying to bring the yang with all my dog pictures) and it is also why the human race will end soon.
Not that the world needs (more) pictures of children, necessarily, or cats or dogs or even quokkas.
Or octopii with soft drinks or perfect radburn suburbs for that matter. Or rear lanes in Forrest or the Dickson library. All things considered.
(NB later clarification: I don't just hang round the schoolyard taking pictures of kids etc etc I mean my nephews and nieces or children of friends etc whose company I enjoy as people and who do funny or interesting things worth taking pictures of).