A seven year-old girl Mykayla Comstock with a rare form of cancer in Oregon uses medical marijuana as part of her treatment. Mykayla's mother says she gives her daughter marijuana pills to combat the effects of chemotherapy, but her father, who lives in North Dakota, worries about the effects of the drug on her brain development.

Oregon law requires no monitoring of a child's medical marijuana use by a pediatrician. The law instead invests authority in parents to decide the dosage, frequency and manner of a child's marijuana consumption.

The Oregonian reports that 52 children with a qualifying medical condition are currently served by the Oregon Medical Marijuana Program. Pain, seizures, nausea and cancer are some of the conditions treated.

This isn't the only state treating children with prescription medical marijuana. Last May, the Associated Press reported 44 medical marijuana cards were issued in the state of Michigan. The American Academy of Pediatrics told the AP at that time it did not have a policy on medical marijuana, but was working on one.

Medical marijuana is currently legalized in 18 states in addition to Washington D.C., with Massachusetts being the most recent state after its voters enacted legislation during the November elections.