Young men who had smoked marijuana recreationally were twice as likely to be diagnosed with testicular cancer than men who have never used marijuana, according to a US study.

Researchers whose findings appeared in the journal Cancer said the link appeared to be specific to a type of tumor known as nonseminoma.

"This is the third study consistently demonstrating a greater than doubling of risk of this particularly undesirable subtype of testicular cancer among young men with marijuana use," said Victoria Cortessis of the University of Southern California, Los Angeles, who led the study.

"I myself feel like we need to take this seriously now," she added, noting that the rates of testicular cancer have been rising inexplicably over the past century.

The research isn't ironclad proof that the marijuana is to blame, and even if it is, the danger isn't overwhelming.

Please LIKE our Facebook page - it makes us stronger