THE past couple of years were momentous for me  I was finally able to reveal my true self at work.

I’m transsexual. I was born male but knew from an early age that I was different. I’ve always felt like a female. In 2008, I started living as a woman in my personal life, and the next year I started going to work as a woman. It’s been a sea change both for me and for my colleagues, some of whom knew me for more than 23 years as a man.

I’m a liaison between the United States Geological Survey and the Environmental Protection Agency. I’ve worked for the survey, my home agency, since 1987, and the E.P.A. since 2001. I’m assigned to an E.P.A. office in Dallas. Using geological survey data and other information, I draw maps for E.P.A. emergency-response personnel. The maps allow the agency to evaluate an emergency situation and come up with a plan.

I wanted to transition, or move from one gender to another, earlier. But I was worried because the E.P.A.’s nondiscrimination policy did not include explicit wording to protect transsexuals. Not all federal agencies’ diversity policies are identical. By contrast, a directive by the Interior Department, which includes the geological survey, explicitly protects people whether they are heterosexual, homosexual, bisexual or transsexual.

I had reached a point where I felt I didn’t have a choice. I was severely depressed and knew I had to transition in order to be happy.