Having raised two daughters, and now raising a son, I had come to the conclusion that it was much easier to raise boys. Girls go through that difficult teenage time where they're all emotional and hormonal, making it difficult to rationalize with them. We worry about our daughters getting tangled with the wrong guy and being victimized because their emotions are in the wrong place ... things like that. I'm now of the opinion that boys are not really any safer, or easier to raise, than girls. The concerns are a little different, but I think they also go through a time period where they can easily be victimized.
I think I have to somewhat agree with Goober (per comments in previous related discussion) that single parents homes are part of the problem. Homes where two parents are always trying to make ends meet and find some sort of personal satisfaction in the ongoing struggle to get ahead is probably another factor. I don't think that single parents raising children is the problem, but moreso the fact that many single parents set a pretty bad example while raising their children. Mothers, especially (because the children are usually with them) are probably failing their children. They are working, managing but not nurturing children and they most likely have a string of relationships before they remarry. Single parents are probably rather unstable while they are looking to fill their own emotional void. That, in itself, provides a very unstable home and value system for the children. I have known many single mothers that can't cope with their sons enery levels, so they turn to ADHD drugs to sedate their children ... whereas the best thing would be for the moms to take their children hiking for a day (or sports ... some healthy outlet). Children of parents that are not divorced can fall into the same abyss, but I suspect it is much more common in families where the parents are divorced at least once.
I suspect that some parents simply give up on their children when the children need them most. It's sometimes difficult to get into the head of a teenager and be able to communicate with them without them hearing something that isn't being said. They can react to what they think they hear rather than what is being said, and that can take a conversation in the wrong direction quickly ... which can lead to a "shutdown" between parent and child. I really wish that parents would set their worries, fears, goals and personal needs aside more often when they have a teenager that is getting so mixed up they turn their anger towards strangers and acquiantances.