Twenty years ago computers were very big and bulky. Once you put them down on your desk, you wouldn't move them. They emitted EMF radiation, but were relatively safe, because they were primarily used a safe distance away from the body.
Today, computers and other devices are extremely portable and can fit on your lap or in the palm of your hand. Today's devices have many times more computing power, and are used much closer to the body, thus creating health risks that did not exist 20 years ago.