It was three years ago that our daughter, then 17 years old, shocked me with the announcement that she was male. Our child asked us to use male pronouns and the name Sebastian.

As we tried to be accepting and supportive parents, there was so much we just didn't understand. People who are in the process of changing their gender refer to themselves as being "in transition." But transition isn't limited to the trans person -- parents experience a transition as well. For us, it was a transition that was foisted upon us and was a confrontation to what we thought we knew about gender identification and sexuality. Our transition was trying to construct a new understanding of how the person we had known to be our daughter could now be our son.

As a child, Seb had a few dolls and spent time with other girls, but he was never a "girly girl." His awareness of his maleness emerged for him through middle school and high school as he found himself in a world of boys through his interests in math, philosophy and politics. He explained to us that he felt like "he belonged" in a group of guys. Originally, this rankled my wife:

At first, I thought, "Heck, who wouldn't want to be a boy?" Growing up, a lot of the activities I preferred were boy things -- collecting stamps, fiddling with electronics. (Yet, even though I went to a progressive school, the girls were forced to take dance; I wanted to take shop.) Then my feminism kicked in. Was Seb being a defector to the feminist cause? I had grown up through this transformational time when women could finally be successful on their own terms. So when my daughter said she was male, on one level, I was offended, politically. It wasn't an immediate or thought-out reaction. But, there was this voice saying, "You can't just give up! Fight for a woman's right to do and be whatever she wants!"

We had read about little children who claimed different genders -- biologic boys who acted like girls. Biologic girls who declared they were boys and acted and dressed boy-like. Although Seb was binding his breasts and hiding the parts of his body that marked him as female, he wasn't trying hard to look male or act like a guy. In fact, he still talked about how much he loved to crochet! He still wore an earring and would sometimes coo at things that delighted him. The incongruity was hard to grasp. On top of that, he just didn't seem like a guy to us. As his father, I thought I knew what a male was, but I couldn't see my child as male.

So, in many ways, our transition as parents was not in the knowing of Seb's new status, but it was in the seeing and believing of our son as a boy. We saw our child binding his chest with a heavy elastic binder. We saw him wearing shapeless clothes to hide the wrongness of his body. But we couldn't quite see this person who we always knew to be female to now be a man.

Then, about one-and-a-half years ago, at the end of the Christmas break, Seb was home during his first year of college and we were in Rockefeller Center. He was taking a late-night MegaBus back to school and it was nearly midnight. Stores were about to close but my wife and Seb had to go to the bathroom. The guard in Rockefeller Center pointed to my wife and directed her to the women's room. Then he pointed to Seb and automatically pointed to the men's room.

In that moment I was shaken: other people were seeing Seb as male. As male! Yes, we would Skype to him while he was in school that first year and I would ask, "Do people ask you if you are a girl or a boy?" (He said they didn't ask.) But here was proof: a stranger, without asking, perceived my child as a guy. Later it dawned on me that there might be a time, some day in the future, when I would be faced with the need to walk into the men's room alongside Seb. I wasn't ready for that.

As time went by, Seb continued to talk about starting testosterone. He wanted to legally change his name and to change the F to an M on his driver's license and birth certificate. None of these desires were quite as disconcerting to me as taking the step of getting top surgery (a mastectomy). Just the thought would give me a queasy feeling. It was so permanent. My wife said:

At the first mention of mastectomy, it felt like another sexist plot -- to get rid of those horrid things, breasts, that represent weakness and womanhood. It wasn't a logical thought, but I recoiled at the idea that you had to destroy a part of yourself in order to qualify as male. But as Seb spoke of how upsetting it was to see a body that didn't represent who he was, I understood his anguish and wanted him to be able to feel good facing a mirror.

We were trying our best to be supportive parents, but there were always questions, most not spoken to Seb. We read what we could and spoke to a psychologist who specialized in working with families of transgendered children.

I wondered if this could all be something that was hormonal. Maybe it was a deficiency in estrogen that was leading to this wrenching dysphoria. What if medical science could find a reason for it that was medically correctable? I thought, "Before you change your life and your name and carve up your body, what if there is a way to reverse it?"

We came to understand (and finally accept) that although the neurological science of gender was still relatively new, gender identification is not a medical, hormonal or psychological condition that can be reversed. It is fixed. It is embedded at a deeper level, hardwired separate from one's biology.

At the same time that we were revising our understanding of gender, we were also puzzling over our child's sexual orientation. When Sebastian was "a girl" in high school, he told us that he was gay (although he always seemed more interested in guys than girls.) After Seb came out to us as transgendered, he clarified that; yes, he was gay, but he was interested in males. More specifically he was in a relationship with another female-to-male transgendered person -- just like himself.

It sounds kind of Neanderthal. When Seb identified as gay, I thought, "OK, my daughter is attracted to girls." Then when Seb said, I'm sure I'm transgender, I thought, "Seb wants to be a male to be with females. He'll be taking testosterone and then he'll become really interested in girls." Then when Seb said he was in a relationship with someone who was female at birth and who, just like him, identified as male, I was honestly puzzled. They were almost like twins - not only in their gender and sexuality, but even in appearance. But is relationship about opposites attracting? That's often not true in heterosexual relationships and may be even less true in gay relationships. I, like most people, easily conflate sexuality and gender. I thought that transgendered people wanted to slip into traditional roles and relationships in their new gender. Not necessarily.

As we've gone through this parental transition, we've never felt less than two or three different ways about our child's journey at any one time. A lot has changed for us over the past three years. We've felt more confident telling family and friends. We stood by our child's side as he went through surgery last month. We watched as bandages were removed. We welcomed his partner into our lives and our family. And we celebrated as he told us that for the first time in his adult life he could run down the street and feel free -- able to breathe and not embarrassed by his body.

What's really changed is the sophistication of my understanding of gender. Gender, just like sexuality, is on a spectrum. There are sexual dimensions, gender dimensions, how you present yourself, and how people see you. What I've learned is that instead of two choices for each dimension, both gender and sexuality have a multiplicity of variations -- far more than Kinsey ever documented.

Society hasn't caught up with these ideas yet. Our hearts go out to anyone who is not on one of the binary positions and is struggling to find a place where they fit in. This is where family love and support need to step up, rather than flee, all of us transitioning together.