It's literally unhealthy to not jackoff, unless you want prostate cancer.
Basically, the story of jacking off being unhealthy began in ancient Greece. It wasn't so much masturbation as it was excessive ejaculation or not ejaculating enough. Masturbation became a popular target in the 18th century, Samuel Tissot. Tissot suggested hydrotherapy and meditation as a remedy for masturbation-induced illnesses. Eventually it was discovered that even children masturbated. Hence the genesis of medical circumcision.
Oh, and for reference, anything you hear about masturbation (though some particular techniques, e.g. autoerotic asphyxia, are dangerous) being unhealthy, just remember that talk radio is about as useful a source as alt.flame