There is no single gene, or set of genes, that determines whether or not a person will become an addict

There is no single gene, or set of genes, that determines whether or not a person will become an addict. And even if a person's parents are addicts, it doesn't mean they will be too. 

Current addiction research shows that roughly 50% of addiction tendencies are attributable to genes.That's a high percentage, but it still leaves half of the equation up to the environment and personal experiences. The addiction gene myth lulls many people into a false sense of confidence about their own drug use while paradoxically also discouraging many addicts from seeking treatment.