Mary S. Applegate, MD, MPH, Bureau of Women's Health, New York State Department of Health, Empire State Plaza, Corning Tower, Room 1882, Albany, NY 12237 and Joseph Nicholas, MD, Preventive Medicine Residency, University at Albany School of Public Health, 1 University Place, Rensselaer, NY 12144, 518-474-1911, msa04@health.state.ny.us.

Since 1972, transsexual individuals born in New York State have been able to obtain new birth certificates indicating their corrected gender following sex reassignment surgery. Analysis of applications for birth certificate gender reassignment (BCGR) can provide a population-based estimate of the incidence of gender identity disorder.

An anonymous log of BCGR applications has been kept since 1997, recording only the year of request, the applicant’s birth year, and the direction of the sex change (male-to-female vs. female-to-male). The following descriptive statistics were calculated for the entire cohort and by gender: number of requests per year, average age at time of request, ratio between male and female applicants, and population-based incidence. The incidence was calculated in two ways: one used a birth-cohort denominator, and the other (consistent with international incidence estimates) used the current adult population as denominator.

From 1997 through 2003, 117 individuals applied for BCGR. Ninety-five (81.2%) applied for male-to-female reassignment, compared with 23 female-to-male applicants, for a ratio of 4.3 to 1. The average age of male-to-female applicants was 45.2 years, while the average age for female-to-male applicants was 39.7 years. The birth-cohort incidence was 11.9 per 100,000 live births, and the current-population ratio was 0.19 per 100,000 adult population. The time between sex reassignment surgery and birth certificate change ranged from weeks to decades.

This is the only population-based, epidemiologic study of gender identity disorder in the United States. While BCGR is only a proxy measure, the findings (incidence and gender ratio) are similar to European studies.

Learning Objectives:

• Discuss the challenges in estimating population incidence of gender identity disorder.
• Describe the incidence of birth certificate gender reassignment requests in New York State by age of requester and direction of change.

Keywords: Gender, Statistics

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.