Transsexualism in female monozygotic twins: a case report.

OBJECTIVE

A case report is presented of a gender identity disorder involving a pair of female monozygotic twins who requested sex reassignment. As far as we know, this case is the first in psychiatric literature and supports a genetic aetiology of this disorder.

CLINICAL PICTURE

The patients were two 18-year-old female monozygotic twins who had showed symptoms of transsexualism since early childhood. They had no other physical or psychiatric disorder except borderline mental functioning.

TREATMENT

The patients were referred for sex reassignment.

OUTCOME

They were lost to follow up after initial evaluation.

CONCLUSION

In addition to other possible (yet not confirmed) causes of transsexualism, a genetic basis for this disorder is suggested by this case.