Parents are angry after a kindergarten lesson had a student's transgender reveal occur mid-class.

The incident took place last year after a Rocklin Academy Gateway teacher gave the lesson on transgenderism because a boy in the class is transitioning to a girl, reported FOX40.

The California charter school and parents are now battling over whether the lesson was appropriate or if the kindergartners were too young to understand.

Parents of students at Rocklin Academy Gateway in Rocklin, California, are angry after a kindergarten lesson had a student's transgender reveal occur mid-class in June 2017 (Pictured, parents at a school board meeting on Monday night)

The kindergarten teacher (pictured), who has not been named, read two books meant to explain 'transgenderism' to children between ages four and eight because a student in her class was transitioning from boy to girl

The teacher introduced the five-year-old student to the class as a boy. He went to the bathroom and emerged dressed as a girl, revealing her 'true identity' (pictured, Rocklin Academy Gateway)

During the lesson on the second-to-last day before summer break, the teacher, who has not been named, read two books, I am Jazz and The Red Crayon. Both are meant to explain 'transgenderism' to children between ages four and eight.

However, in what critics are calling a 'transition ceremony', the teacher introduced the five-year-old student to the class as a boy. The student then went into the bathroom and emerged dressed as a girl.

The teacher then reintroduced her to the children, and explained she was now a girl with a girl's name and was to be called that from now on.

Many parents said they had no idea the lesson was coming and weren't notified it occurred until a week later when a letter was sent out.

Concerned parents went to the Pacific Justice Institute and the California Family Council to represent them.

'These kids who had never struggled with their gender identity before are all of a sudden scared they could be turned into a boy,' Greg Burt, director of capitol engagement with the California Family Council, told FOX40.

The teacher who read the books defended her actions during a school board meeting on Monday night.

'I'm so proud of my students, it was never my intent to harm any students but to help them through a difficult situation,' she said.

Many parents said they had no idea the lesson was coming and weren't notified it occurred until a week later when a letter was sent out (Pictured, parents speak at Monday's school board meeting)

The district says the books were age-appropriate and fell within their literature selection policy. Unlike sex education, the topics of gender identity don't require prior parental notice (pictured, one of the two books read to the class)

However, the school conceded a policy change and said outside books will now be approved by administration (pictured, one of the two books read to the class)

But parents say they should have been told.

'My daughter came home crying and shaking so afraid she could turn into a boy,' one parent said.

The district says the books were age-appropriate and fell within their literature selection policy. Unlike sex education, the topics of gender identity don't require prior parental notice.

The school also argued that not reading the books would have put them at risk of discrimination and could expose them to a potential lawsuit.

However, Rocklin Academy conceded a policy change and said outside books will now be approved by the administration.

Legislative manager at Equality California Jo Michael, who is a transgender male himself, told FOX40 early education is key to helping children understand transgenderism.

'Most people have a sense of their gender identity at age three or four,' he said.

'It's important to note that the other students really do need to have that opportunity to engage and hear from the transgender student.'