I Learned It By Watching You Anti-Drug PSA

In this classic public service announcement from the 1980s, a father confronts his son about a box of drugs in the closet. The son breaks down and tells him, You, alright! I learned it by watching you!

This commercial draws a direct line between parent and child drug abuse. Assuming that this is true, can modeling account for this? Might there be another reason children of drug users would also use drugs?