Patients commonly explain that 'Bad teeth run in the family". The implied message is that they themselves are not to blame for the state of their mouths. While genetics obviously plays a role in determining the likelihood of developing all sorts of health problems, so do a person's habitual patterns of behavior.
My grandmother wore two full dentures by the time she was middle age and both of my parents lost about half their teeth by the time they were senior citizens. I myself, although in my 50's, have not lost a single tooth. Why?
Although I do not know for sure, I believe the choices they made and their lack of a good dental IQ are the reasons for their extensive tooth loss. All three were chain smokers for most of their adult lives and I do not believe any of them took good care of their teeth until it was too late. Poor brushing techniques, poor diet,lack of frequent tooth cleanings, and nicotine from cigarettes probably were responsible for their tooth loss. All eventually developed adult onset diabetes which compounded their tooth problems.
Although I am far from perfect , I do not smoke, I brush regularly with an electric tooth brush, floss and get regular cleanings. These habits are most likely responsible for over coming any 'genetic predisposition' that might lead to tooth loss.