Is addiction hereditary? There is some evidence for it. There is also evidence that lots of mental disorders, from hoarding to schizophrenia, can be passed down through genes. Here we see evidence of a gene that appears with folks having internet and nicotine addictions:
There is a ways to go before we understand much of anything about genes, but there is one thing we do know about addiction: it is treatable. Therefore, genes may give one a predisposition to addiction, but they do not make us addicts.
There are plenty of people who have given up smoking and the internet. What it requires is a treatment. We must not become fatalistic about such studies and abandon ourselves to 'fate.'
We are more than our genes...