Twins are Concordant for a Trait When ____

Question

Twins are concordant for a trait when ____.
A) both twins share the trait with at least one parent
B) only identical twins have the trait
C) only fraternal twins have the trait
D) both twins have the trait
E) all of the twins' siblings have the trait

Accepted Answer

Twins are concordant for a trait when both twins have the trait, regardless of whether they are identical or fraternal. This means they share the same genetic material and are more likely to have similar traits compared to non-twin siblings.