There is always that possibility, isn't there?
The really good news? I was the alcoholic/addict for my family and had been sober for almost 30 years when I found them.
My birth father was the superintendent of schools when I graduated High School. He was a senior in college when my mother became pregnant. ALL my new siblings agree that he never knew. He was in Korea (the war) when I was born...
So, I was really lucky. Really good family and structure on both sides...