I was able to retrieve one of my reviews, which had been archived on another site:

When Aidan Became a Brother by Kyle Lukoff

Sad, confusing, and regressive story of a little girl who is presented to the world as a boy simply because she does not identify with sexist stereotypes. It's a depressing trend in modern picture books. A young child no than four or five years old is presented as not liking stereotypical things associated with their biological sex. These preferences are then used to support the idea that in fact the child is not their biological sex at all. In this story young Aidan doesn't feel like a girl. What it means to feel like a girl is never explained. Why a female child is not allowed to have masculine interests, masculine clothing, a short haircut, or a boyish bedroom without being told she is a boy is a mystery to this reader. 'They changed his bedroom into a place where he belonged. He also took much better care of his new clothes.' The fact that a little girl can have a boyish bedroom is never acknowledged. The fact that a little girl can wear clothes bought in the boys' section of a store is never acknowledged. Instead these things are presented as proof positive that this young child, again a girl of preschool age, is somehow a literal boy. There is no indication this child hates her body, only that her feminine name, clothing, and bedroom don't feel right to her. Not conforming to sex role stereotypes is presented as a valid reason to say to the world that a child is a member of the opposite sex and should have been born as the opposite sex. I simply do not understand how these messages are passing for progressive. As a committed feminist of many years, women have spent decades fighting the idea that there is only one way to be a girl. It's very sad that young female children today are being told that if they are insufficiently feminine they may actually be transgender instead of their biological sex.

I'm glad to find it because this was, in fact, my only in-depth review. At one point, it was one of the most popular views for this book. It had at least 11 likes, which just goes to show that many readers are not buying into this ideology being pushed on children.