What a load of rubbish, nothing is "wired" to someones DNA. It is a learned behavior and picked up from the environmental setting someone grows up in. It is not a gene, but unfortunately whoever the guardian is to a child can have a huge impact on their development as a person. If you live around someone who smokes a lot, you're much more likely to pick up this habit. If you're around someone who flaunts that they are betting money on whatever, it's not as bad as smoking which has an addictive chemical property, you might be influenced into thinking it is less dangerous. Parent's and guardians have a massive responsibility to teach their children good behavior and it is very easy to pass along bad habits without even realizing.
Medical studies and research said so, even if we disagree, we don't have valid proof to refute their statement. All we have is just some personal experience and personal belief that makes it a bit biased.
I myself disagree with it but have no valid proof that it does not exist. So I won't bother about gambling being inherited or not. What matters is how to cope with it to avoid gambling addiction. Prevention is always better than cure, assuming it does exist, I wanted to know how to prevent this kind of situation from developing a gambling addiction.