Do you have a sister? This is the “question of the day” that greets us as we enter my twins’ preschool class. My heart sinks. Question like these can be difficult to navigate in my family. Can we just say sibling?

One of my twins was born a boy but, for the moment at least, identifies as a girl. This has evolved from insisting on wearing dresses by the age of 2, to wanting to go to the bathroom with the girls at 3, to firmly identifying as a girl, crying if referred to as a boy, by the age of 4. And so, the debates on what exactly constitutes woman and sisterhood are personal and immediate. But as it turns out, everything I need to know about sisterhood, I learned from a 4-year-old.

I am in no rush to define my child as anything; who knows how she will identify years from now? But the world does insist on forcing the issue. The ambiguity of my child’s gender makes people decidedly uncomfortable, and it often seems that conformity is more important than what is best for my child. Complete strangers feel free to tell me that I should force my child to wear “boy” clothes. My sister believed it was simply a matter of providing more “boy” toys. The pediatrician said we had to get her out of wearing dresses because she was too pretty. People seem to feel that they deserve an explanation when they ask for the twins’ names and one of those names is a typically male one.

My child’s evolving gender identity has been part of a learning curve for me, our extended family, her teachers and classmates. Though I am an academic well trained in feminist theory and the idea that gender is a social construction, having a child who presents as transgender has made me far more sensitive to how gender is defined and policed.

All of this has made me an ambassador of sorts for transgender issues with my children’s teachers, other parents and school officials. I have explained to other preschoolers that people can be whatever they want to be and that there are lots of ways to be a girl. I am always and everywhere an advocate for my child. But even I sometimes revert to male pronouns.

Only one person has taken every transition in stride, often, in fact, explaining them to everyone else. That is her twin sister. It was she who explained to me that the reason her twin didn’t want to go to school was because she no longer wanted to go to the bathroom with the boys. Once we knew this and the school agreed, the problem was solved. It is she who corrects me, and other people, if they refer to her twin as he. She generously shares dresses and princess toys and fire trucks and doctor sets. She accepts her twin as she is, even as this changes and evolves, because she loves her. She knows her as she is and has no conception of how she is “supposed” to be.

For her, the definition of gender, the politics of it, and the way some people may look askance don’t matter. When someone recently referred to her twin as her brother, she quite forcefully yelled, “That’s my sister!” Her twin is who she says she is. They are a source of strength for each other, a team (except, of course, when they are bickering the way 4-year-olds do).

So, do you have a sister? I read the question to my twins and the joy of recognition lights up their faces. They both, without hesitation, answer yes. In light of the recent suicide of Leelah Alcorn, who killed herself because, “The life I would’ve lived isn’t worth living in … because I’m transgender,” can’t we agree that our common assumptions are not more important than people’s lives? One report among many shows that transgender people face pervasive discrimination, are more likely to live in extreme poverty, and over 40 percent attempt suicide.

As parents and sisters and friends, our response must be, as Jennifer Finney Boylan argues, to read, write and scream against the injustice of it all. We can choose to accept our children for who they are, in all their wonderful complexity, and liberate ourselves from the narrow conceptions that gender places on all of us.