In this month's British Medical Journal, there's a report on a study demonstrating the relationship of sleep to brain development in kids. It is called the Millennium cohort Study, and it followed 11,000 children. Those children who demonstrated irregular bedtimes up to the age of three were the most negatively affected when it came to reading, math skills and spatial awareness. When followed over time, they continued to lag developmentally even by the age of seven -- and girls more than boys. The authors concluded that the first three years of life seem to be a particularly sensitive time for sleep and its relationship to brain development.