I’m not asking if someone could have more addictive tendencies, or even things such as depression that could run in the family. I’m asking along the lines of more of a personality trait, such as coldness, a cheery outlook, a “wild child” when the adoptive parents are reserved, things like that. Is it the environment that shapes things like that, or could it be that genetics shape a personality?

Suggested Reading:

Introduction to Genetic Analysis (Introduction to Genetic Analysis (Griffiths))The author team welcomes a new coauthor, Sean B. Carroll, a recognized leader in the field of evolutionary development, to this new edition of Introdu... Read More >