The first sales of legal recreational marijuana began in Washington on Tuesday. The Evergreen state joined Colorado as the only two states to legalize all marijuana.

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When it comes to keeping your child away from drugs, parents are dealing with more challenges now than ever.

The Metropolitan Drug Commission in Knoxville said the legalization of marijuana has teens reconsidering marijuana use. It's now making it harder than ever for parents to explain to their child why they shouldn't use it.

"The scare tactics don't work anymore," said Deborah Huddleson, with the Metropolitan Drug Commission. "They need to make sure to let their kids know the facts."

Huddleson said social media has changed everything. Children can look up anything they want on computers and answers are right at their fingertips.

"They can't go and tell their kids something that isn't true for a scare tactic because they are going to just go and look it up," she said.

Research said there is no magic technique in preventing drug abuse, but parents have a big influence on their teenagers.

Huddleson said it's important to talk openly about the drug to help them make the best decision.

"They should make it where it's not uncomfortable for their kids to want to come to their parents to talk about it. It should be an open dialogue, an open conversation for them," she said. "They do need to make sure they are being the parent and not being their kids' peer."

Even though marijuana is legal in two states, the FDA still hasn't approved it.

While some question its dangers, Huddelson and the MDC are urging parents to talk to their kids.

"Marijuana use disrupts the brain function, it's critical to motivation, memory, judgment, and behavior control," she said.

In Tennessee, possession of any amount of marijuana can land you in prison for up to a year, with a mandatory fine of between $250 and $2,500.

Twenty-three states allow marijuana to be used for medical purposes. Tennessee is not one of them.