The new Science of Intersex

R. JOneS was surprisingly relaxed and jovial considering that he had driven two hours from Bakersfield to Los Angeles to have his thirteen-month-old child examined by half a dozen doctors. no doubt he was sustained by his faith: on his T-shirt was boldly emblazoned “Got Jesus?” The examination rooms are usually crowded in the Intersex Clinic (now the Disorders of Sex Development [DSD] Clinic) at UCLA, where experts from pediatric urology, endocrinology, genetics, and psychiatry gather to assess children with DSD and counsel their parents. I am the psychiatrist attending in the clinic and the most recent addition to what had long been exclusively a pediatric urology clinic. However, given the growing controversies over the past two decades concerning corrective genital surgeries in intersex infants, it had seemed prudent to include a variety of specialists in arriving at a consensus on treatment. Little Ben was an active, well-nourished baby who had had an unusually tumultuous gender history. After the physical exam was completed and the room cleared out, I got to talk to Mr. Jones privately. The Joneses had been told they had a baby boy when he was delivered at a small, rural hospital. But a few days later they received a panicked call from the hospital: “Your child’s a girl! Take him to UCLA right away for surgery to become a girl!” At least that is how Mr. Jones recalled the shocking answering machine message. Chromosome testing had uncovered that Ben was 46XX: he had the normal number of chromosomes (46), but he had two X sex chromosomes instead of the usual XY chromosomes of males. More detailed genetic testing found that he had an SRY gene on one of the X chromosomes.. SRY (Sex-determining Region of the Y) was only identified two decades ago after a half-century hunt for a gene on the Y chromosome that induced the developing embryo to develop testes rather than ovaries. The reigning hypothesis was that once the testes start to form, they generate all the subsequent hormones that promote the development of male internal and external genitalia. It was thanks to rare patients like Ben that in the 1980’s geneticists were able to isolate SRY. A rare genetic cross-over event during sperm formation can lead to SRY transfer from the Y to the X chromosome, resulting in a baby with penis but XX chromosomes (like Ben) and, conversely, a baby with a vagina but XY chromosomes (and no SRY on the Y chromosome). Such socalled “complete sex reversal” is exceptionally rare among the ESSAY