If your 10-year-old is becoming aggressive day-by-day blame the hormone cortisol for the increased aggression in the young boy says a new study. Findings by Spanish researchers confirm that children especially boys who experienced the greatest increase in levels of aggression by ten years of age were those whose cortisol levels had also increased during eight-to-ten years of age. The research team studied the relationship between hormones and aggressive behaviour in girls and boys between the ages of eight and ten. They measured the levels of three steroid hormones -- testosterone estradiol and cortisol -- and analysed the effects of
