I find it more of a concern that the kids are able to get hold of drugs etc. in the first place. Perhaps an older brother or sister, and in some cases parents, but I think it would be more likely an older kid they knew in the area. But I do agree this issue is mostly a case of bad parenting, as the child should have been at least educated about drugs to some extent by that age. I think this is a parent's responsibility as the current school curriculum is so outdated.
And how on earth do 10-year-olds have sex? Surely puberty strikes this early only in a tiny number of cases? I went through a swift puberty, completely over by the age of 12, but I certainly don't think i was ready, physically as well as mentally, for sex until a few years later. Perhaps it is partly a case of the society we live in today, where children are under increasing pressure to grow up before they are ready, from the media as well as their peers, but I find it hard to believe children are having sex this young :| It is baffling and disturbing.