Source: AP 18 Feb 2009, via Does God Exist? (John Clayton)
The Fred Hutchinson Cancer Research Center released a report on February 9, 2009, revealing that there is a high correlation between marijuana use and testicular cancer. The cancer is nonseminoma, and it has increased rapidly in recent years, especially in Europe, where cases have risen by 6 percent.

The study of 369 testicular cancer patients between the ages of 18 and 44 showed a 70 percent increased risk for the disease. It is known that marijuana strongly affects hormonal production, so the finding was not a major surprise.

*  *  *  *  *

Source: Science News, February 9, 2008, p. 85.
The big push for legalization of marijuana took another hit in recent studies on the damaging effects of marijuana on the gums. Studies have shown that people between the ages of 18 and 32 who use marijuana once a week were three to five times as likely to have periodontitis, in which the inner layer of gums and bone pull away from the teeth. Adding this to the proven lung damage pot causes makes recreational and medical use of marijuana very unwise.

For further ill effects of marijuana use, read this article.

*  *  *  *  *

Source: The Economist,11-17 February 2012, pp.31-32
"Methamphetamine use, which spiked several years ago, has fallen off. But the past ten years have seen a rapid increase in recreational use of prescription drugs. In 2000, 1.2% of Americans had misused these drugs, mostly powerful painkillers; by 2010, the proportion of users had doubled to 2.7%, second only to marijuana, long the most commonly used illegal drug."