Michael and andrew are siblings who grew up in the same home environment, played together on the same little-league baseball team, and went to the same school. during early adolescence, their parents divorced and both boys went to live with their mother. the fact that michael and andrew have similar personalities is most likely due to:

Genetics

Explanation:

In humans most of the personality traits are characterized by genetics which are inherited by their parents. Off springs tend to behave or have the same personality or characters as those of their parents.

Other factors which influenced the behaviors or characteristics of a person is the environment where they grow.

In the context, Andrew and Michael grow up in the same environment and had the same experience in their adolescence. Both the siblings have the same personalities because they have inherited them from their parents. According to study, personality traits are less affected by the shared environment.

Hence the answer is --- Genetics.