(In defense of X, that’s solid logic. His one mistake was in applying it to Rutile.)

The child’s question come in a rapid succession that Rutile listens to in stride - until the last one, which leaves them confused and slightly taken aback. They have fielded many questions about their species and occupation thus far (the lab coat draws both respect and disdain, sometimes at the same time), but never about such blatantly human concepts.

“I am Rutile,” they introduce themselves, in the same even tone as before, and gesture to their chest with one hand. “I am named after what I am made of. I don’t know your name, unfortunately, or what you are made of, though you look human enough. As for being a boy or a girl... there is only one rutile, and I am that.”

That ought to be clear enough.