In his April 19 commentary, Nicholas V. O'Hara, an inspector in the Ramsey County Sheriff's office, made three claims about the use of medical marijuana that are baseless.

• That marijuana is a gateway drug. There is sound evidence that marijuana is only a gateway drug because it is purchased from the same people who sell harder drugs. But that would not be the case with the distribution of medical marijuana.
• That marijuana may cause cancer. This may be true when smoked, but medical professionals suggest that marijuana be vaporized for safer inhalation.
• That marijuana use rose among teens in seven of the 12 states where medical marijuana is legal. Yet O'Hara doesn't provide any information that demonstrates a correlation.

MICHAEL D. MOLZAHN, WOODBURY