I have three children - two boys aged 12 and 9 and a little girl aged 3. While they tend to get on well when all together, my boys have recently started bickering to a point that makes me uncomfortable. I know you have to expect some arguing between siblings but this has got to the point where the exchanges are quite aggressive and I am seriously worried if I don't do something they will end up hurting each other. I put much of the behavior down to age, my eldest has recently become moodier than in the past but I am concerned I am missing an underlying issue - even though talking to them both has not revealed anything. Any ideas how to approach this?