One of the most hard-won achievements in life is finding out and knowing who we really are. For three young people in an upcoming National Geographic documentary, discovering their true selves was just the beginning...

American Transgender is a new work from writer and director Leslie Schwerin that unfolds in verite format, with the subjects speaking for themselves without narration. They recount becoming aware of their differences as children, and then discuss their courageous decisions as young adults to transition through surgery to the opposite sex. American Transgender premieres Tuesday, May 1 at 8 p.m. ET on the National Geographic Channel.

The documentary uses evocative montages of childhood pictures to introduce us to the show's subjects. Sarah and Jennifer go on to have hormone treatments and surgeries to become Eli and Jim. Alex, a young man, does the same to transition to Clair.

All three talk extensively about growing up having to "act" the role of girl or boy - all while being mocked and feeling trapped and tortured in the wrong body.

One of the most uplifting parts of American Transgender is seeing the support and acceptance the three received from their families before and after the transition process. Coming out as gay - as Alex did as a teenager - is difficult enough, but revealing a desire to change one's sex presumably doubles the weight.

It's reassuring to see parents so committed to their children's happiness. Jim's mother, Diane, says, "we adjusted our thoughts from "tomboy" to "gay" and we moved on. We were getting used to that, and all of the sudden, (Jennifer) said my name is going to be Jim'." She laughs, "I was just getting used to gay." (Jim at right, after transition.)

Making the personal decision is to transform gender is just the first step. The physical difficulties of the process and the challenge of passing for the opposite sex are openly discussed.

Eli talks openly about his frustration during transition, and how after months of treatments, he still was being called "ma'am" by grocery store clerks. And Clair's story, beginning as it does with her shopping for a wedding dress, takes a surprising, charming turn on which the entire documentary pivots.

In the case of the documentary's three subjects transition was a success, and each have gone on to new relationships in their new identities. They all experience happy endings, for the most part, whereas some previous documentaries on transgenderism have profiled transitions that haven't progressed as well.

To its credit, American Transgender is about healthy well-adjustment and not a gratuitous look at alternative lifestyles. These are brave journeys of self-acceptance for people who not only went inward to get to know who they are, but were then able to summon the courage to go forward into a process that included surgery and chemical treatments, knowing there was no guarantee of success.

As Eli (right) says, "I wanted my body to look on the outside how I felt on the inside."

His close friend, Antonio, another female-to-male transgender, adds, "there's a choice of happiness and misery. And there's a choice of being true to yourself, or living a lie."

It's worth noting that regardless of gender, identity, economic status, that's good overall advice. And in that way, there is something for all of us in American Transgender.