Which Piece of Data Would Provide the Strongest Evidence for the Idea

Multiple Choice

Which piece of data would provide the strongest evidence for the idea that transexuality has a biological basis?

A) The presence of a gene that occurs only in transexual individuals
B) An increase in the number of transgenders seeking sexual reassignment surgery
C) A study showing that transexual behavior can be suppressed by psychotherapy
D) A study of identical twins showing that one twin is transexual and the other is not
E) A large group of genetic males who choose transvestism over gender reassignment