The American tax office has been dragged into the debate over whether sex-changes are genuine medical treatment or an inappropriate response to a psychological problem. Rhianon O'Donnabhain, a construction engineer from Boston, decided to become a woman in 2001 after having fathered three children. He claimed a US$5,000 tax deduction for the surgery, which the Internal Revenue Service initially allowed. However, the IRS quickly reversed its decision because the operation had been merely cosmetic, and therefore not deductible. O'Donnabhain refused and sued the IRS. The case is now making its way through the courts.

O'Donnabhain, now 64, is supported by the Boston-based Gay and Lesbian Advocates and Defenders as a test case. A psychiatrist at Harvard Medical School, Marshall Forstein, says that an operation is clearly medically necessary. "When did the IRS suddenly become physicians? It's absolutely clear that transgender identity is a condition discussed in diagnostic manuals. It seems the IRS is now in the business of practicing medicine without a licence."