DENVER (AP) — Democratic presidential candidate John Hickenlooper says gun owners should have to be licensed and pass a safety test to own firearms.

The former Colorado governor on Wednesday released a detailed gun control proposal, similar to that of presidential rival and New Jersey Sen. Cory Booker.

The licensing proposal would only affect people born after 2001. Upon turning 21 they would have to pass a safety test to obtain a gun license. Hickenlooper also proposes making the Bureau of Alcohol, Tobacco, and Firearms part of the FBI, and banning assault weapons and 3-D printed guns.

Gun licensing is sure to spark controversy with gun rights groups, who have long seen it as the start of gun confiscation.