Even though some people are genetically prone to particular conditions many (but not all) genetic 'predispositions' can be turned on or off through lifestyle factors. The most important of which is what we choose to eat. When the health of immigrants is tracked from one country to another they start to get the diseases of the culture they move to rather than those that were previously deemed hereditary. This is well documented. It's largely down to diet.
The safest bet is a wholefood plant-based diet. Meat and dairy are both known to act as triggers for particular forms of cancer in those who are susceptible. Conditions like Type 2 diabetes can be reversed in as little as a month.
I find it really empowering that so much information is now available and that we can choose to use it ourselves. Taking responsibility feels good.
Not saying it's for everyone, but the option is there for most people.