Much of the data is from observational studies which are subject to many biases, and there is the challenge of isolating and quantifying environmental exposure.
The proliferation of cell phones, iPods and Facebook brings a complicated challenge for parents, teachers and students: The constant exposure to technology and the Web amplifies opportunities for children to bully each other online.
In May, a group of Turkish historians (many of whom challenge the official view that the main cause of death among deported Armenians was exposure and disease) suffered a sharp setback.