A behavioral geneticist would only want to study identical twins, due to their shared genetic code. Fraternal, or non-identical, twins would not reveal anything interesting in such research.

Behavioral Geneticist

A scientist who studies the role of genetics in shaping behaviors, personality traits, and mental health disorders, often through twin and adoption studies.

Identical Twins

Twins that originate from a single fertilized egg that splits and develops into two genetically identical individuals.

Fraternal Twins

Twins that develop from two separate eggs fertilized by two different sperm, resulting in siblings that are genetically distinct.