Question

In one study, when one identical twin had gender dysphoria, there was approximately a _____ percent chance the other twin did too.

Answer 1

The correct answer is:

40%.

In the study Gender Identity Disorder in Twins: A Review of the Case Report Literature, out of 23 monozygotic female and male twins, nine (39.1%) were concordant for gender identity disorder (GID), best known as gender dysphoria. These conclusions allow considering a role for genetic factors in the development of GID.

Answer 2

When one identical twin has gender dysphoria, there is zero percent chance the other twin do too, studies done on identical twins have proved that GD is not shared through genes, it is more a psychological issue, a test practiced on 500 pair of twins revealed that only 20% of the pair of identical twins were transexuals, reaffirming the fact that GD is developed by a particular event after birth, and not by genes sharing, because if it were like that, 100% of the identical twins would experience the same incongruity between biological sex and gender identity.