Tara and Sarah are identical twins. If Tara has bipolar disorder, then Sarah has ________.
A) a 100% chance of developing a mood disorder
B) a 100% chance of developing bipolar disorder
C) a 40-70% chance of developing a mood disorder
D) a 60-80% chance of developing a bipolar disorder

Question

Tara and Sarah are identical twins. If Tara has bipolar disorder, then Sarah has ________.
A) a 100% chance of developing a mood disorder 
B) a 100% chance of developing bipolar disorder
C) a 40-70% chance of developing a mood disorder 
D) a 60-80% chance of developing a bipolar disorder

Quizplus · Accepted Answer

While there is a genetic component to mood disorders, the likelihood of a twin developing a mood disorder is not 100%. The range of risk for identical twins is estimated to be between 40-70%, depending on the specific disorder. Therefore, Tara having bipolar disorder does not guarantee that Sarah will develop a mood disorder or bipolar disorder, but the risk is increased compared to the general population.

Tara and Sarah Are Identical Twins