CHICAGO (AP) — The nation’s leading pediatricians have concluded that medical marijuana is generally not for kids, but they also support more research.

The American Academy of Pediatrics’ revised policy statement says that with virtually no hard proof that medical marijuana benefits sick children, and evidence that it may harm developing brains, the drug should only be used for severely ill kids who have no other option.

Some parents insist that medical marijuana has cured their kids’ troublesome seizures or led to other improvements.

To make it easier to study and develop marijuana-based treatments, the group recommends removing the drug from the government’s most restrictive drug category and switching it to the category which includes methadone and oxycodone.

The academy also repeated its previous advice against legalizing marijuana for recreational use by adults, suggesting that may enable easier access for kids.

The policy was published online Monday in Pediatrics.