Unfortunately we do live in a world filled with many kinds of waves, the natural ones and the human induced ones, for the latter its impacts on health is still controversial, the most studied are probably those emitted by GSM, and it is recommended to use them moderately or at least with earplugs to avoid direct contact with the internal ear and the brain.
Whenever possible avoid waves (wifi, etc.), direct connection (cable) is far more secure, and not just for your health, for your computer too !