08/01/2012 04:30 pm ET Updated Feb 02, 2016

XX vs. XY

"When did you know for sure?"

Everyone we meet wants to know the answer to that question when they hear we have a transgender child, some because they want to calm unspoken fears about the possibility that their own tomboy daughter or feminine son might be gender-variant, perhaps, but most because they are genuinely interested in a subject that is still a mystery for so many.

I remember Sam always gravitating toward traditional male activities, male friends, and male play, from Matchbox cars and toy CAT bulldozers to baseball jerseys and Bob the Builder reruns. Sam was all boy. When he was 3, a well-meaning preschool teacher sent a photo home with him. The woman was just as pleased to share what fun our child was having at school as Sam was to be hand-delivering a picture that was sure to make the refrigerator wall-of-fame. As I studied the photo of three young children playing house, a sick feeling began to grow in my stomach. In front of me were two girls engaged in traditional-gender-role play, happily assuming the coveted parts of mother and child, and then there was Sam, complete with a fake beard, sportcoat, top hat, and a grin from ear to ear.

When I asked Sam what role he was playing, his tone, more than the answer, caught me off guard. With a confident, don't-you-get-it-Mom inflection in his voice, Sam proclaimed, "I'm the dad!" An even more incredulous tenor ensued when I asked why he was playing that part. "Because that is who I am!" he explained with frustration. I was hoping the answer would have been, "Because they made me be the dad," for I would have much rather dealt with a daughter not standing up to her classmates than a child who was starting to tell us, in the only way a child of that age knew how, that there was a disconnect between mind and body.

The early years were filled with more of these types of anecdotes than I care to remember, each one providing varying degrees of uneasiness for my husband and me. But it was the revelation Sam came home with in third grade that provided us with that proverbial "aha!" moment. In third grade students at our local public elementary school get their first lesson on the subject of chromosomes -- nothing too complex, mind you, just the basic information. As it turned out, that day proved to be a monumental one for Sam, who jumped off the bus in the afternoon eager to share something important.

"I know what is wrong with me!" Sam exclaimed, grabbing a piece of paper and a pencil with an eraser before the back door was even closed.

"There is nothing wrong with you," I replied, scared of where the conversation was heading.

"Look, Mom," Sam said, writing, in large letters, XX, followed by XY. "Girls have XX chromosomes, and boys have XY."

OK, I thought. So far I can deal with this conversation.

Sam continued, "Something happened to my Y: It was supposed to be a Y, but it turned into an X (erasing the bottom stem of a sloppily drawn Y), and that is why I am a girl when I was really suppose to be a boy."

All I could feel at that moment was an excruciating pain in my heart as I thought about the magnitude of the internal struggle my child must be enduring to come away with this self-diagnosis from a simple third-grade science lesson.

I did not try to deny Sam's feelings any longer; instead, I called my husband at work to share Sam's revelation. It was on that afternoon that we both knew we were facing something bigger than we had once thought, something that was never a phase or a choice. While difficult at the time, we will always reflect positively on that day, for it marked the beginning of our journey down a new path -- one that would help our child become who he was really meant to be.