Most three-year-olds are learning how to sing the ABC’s. But children at a New York City preschool were given a lesson on the LGBT’s and parents on the Upper West Side are furious and demanding answers.

A substitute teacher at the taxpayer-funded New York Kids Club, who claims to be transgender, read children a storybook promoting ideas about gender identity.

The book is titled, “It Feels Good to Be Yourself.”

“There are so many ways to be a boy or a girl,” read a passage in the book. “Not everyone feels like either a boy or a girl.”

Parent Vivian Cialini told television station WPIX that parents were not notified in advance and many children came home asking lots of very uncomfortable questions.

“Most of the parents were in shock and clueless of the decision that the school made,” she said. “I believe it’s too early for them to understand. They barely have awareness of their body.”

New Yorkers sounded off on social media platforms accusing the preschool of using a classroom to groom innocent children.

“Absolutely sickening,” one parent wrote. “As a mom of a three-year-old I find this disturbing. Leave these babies alone.”

“A 3 or 4 year old is not your ‘target audience,’” another parent said the LGBT activists. “Leave the youngsters alone. The world is already confusing enough for them. Teaching (this) is inappropriate and groomy.”