I talked to the philosophy group about the "Minnesota twins study", which I really don't know much about. There is an expensive book about the research which looked at similarities and differences of pairs of identical twins but I didn't want to spend the money. I am like some people I knew in college, so full of my own ideas, my own agenda and my own projects, that I don't have time for anything new.
I did read some and did not find what I thought was convincing evidence that any particular amount of genetic similarity actually dictated any predictable amount of identical habits in monozygotic twins raised apart. We got onto this subject because of a discussion of predestination and fatalism. Lynn and I recently read "Inheritance" by Moalem, MD, PhD, The main point of the book is to make clear that genes do affect us very much but that, counter to what we learned in school, we do affect our genes also. Our diet, the radiation we are exposed to and our life experience all affect our genes.
One aspect of gene influence in our lives is addiction, like alcoholism or drug addiction. I was not able to uncover what I thought was conclusive evidence that addition is much related to our genes. In answer to the question "Is alcoholism hereditary?" , this seems to be a typical response:
One frequently asked question about alcoholism is if it is hereditary. As with most other mental disorders, alcohol addiction has no one single cause and is not directly passed from one generation to another in families. Rather, it is the result of a complex group of genetic, psychological, and environmental factors.
I did find statements that many alcoholics are related to other people with the problem but ferreting out what comes from family habits and what comes from some inner propensity to drink, genetic or other, seems something still to be accomplished.
If you are interested, here is a link to some sources and comments from today's discussion: