A decision to fire an elementary school teacher from Georgia has been upheld, after she read a children’s book on gender identity to her fifth-grade class earlier this year.

The Cobb County School Board of Education voted 4-3 along party lines to uphold Katie Rinderle’s termination, overruling a tribunal that had said she should not be fired. “The district is pleased that this difficult issue has concluded; we are very serious about keeping our classrooms focused on teaching, learning, and opportunities for success for students,” the board of education said in a statement Friday.

Rinderle worked at Due West Elementary School, in Marietta, Ga., and read the storybook “My Shadow Is Purple” by Australian author Scott Stuart to her class in March.

The picture-book is about a child who reflects on his mother’s shadow being “as pink as a blossoming cherry” and his father’s shadow that’s “blue as a berry,” and says their shadow is purple. Some parents complained, although Rinderle said others had also expressed their support for the lesson.

Rinderle, a teacher with 10 years’ experience, was removed from her classroom and the Cobb County School District accused her of violating the district’s policies on teaching controversial issues, and urged her to resign or face termination of employment. She was issued an official notice of termination on June 6.

Rinderle sought to overturn her firing, and a tribunal of retired educators, appointed by the Cobb County Board of Education, determined following a hearing that although she had violated district policies, she should not be fired.

However, on Thursday the Cobb County School Board of Education voted along partisan lines to reject the tribunal’s decision, with three Democrats opposing the decision to fire her and four Republican lawmakers upholding it.

School district lawyer Sherry Culves, speaking earlier this month at the hearing, argued that “the Cobb County School District is very serious about the classroom being a neutral place for students to learn. A one-sided viewpoint on political, religious or social beliefs does not belong in our classrooms.”