A mother in Berlin is helping her 9-year-old daughter sue a historically renowned all-boys choir for gender bias.

The girl, whose identity is concealed to protect her privacy, has attempted to join the State and Cathedral Choir in Germany multiple times and has been continuously rejected, the Associated Press reported. The choir said that it didn't deny the girl entry based on her gender, but because she lacked the talent and motivation needed to succeed.

The choir also noted that she may have been asked to join "if her voice had matched the desired sound characteristics of a boys choir,” Berlin administrative court said.

The mother insists that the choir's decision was discriminatory and infringes on equal opportunity rights. In its 554 years of operation, the choir has not admitted a single girl.

The 9-year-old was rejected from the choir in 2016 and 2018 without being given an audition, according to the girl's attorney, Susann Braecklein. In December, the girl was told "a girl will never sing in a boys choir," in a letter sent by the dean of the music faculty at the University of the Arts.

The girl was invited for an audition in March, but was rejected again.

The case has received significant attention, with some siding with the girl and her mother and others arguing that letting a girl sing breaks from history and tradition. Some say that there's a distinct difference between boys' and girls' voices.

Ann-Christine Mecke, a musicologist, told ZDF television that although there are variations between the voices of girls and boys, it's pretty insignificant.

Currently, around 250 boys and men between the ages of 5 and 25 belong to the choir.

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