A plan to storm the girls' bathroom at Alaska's North Pole High School ended with a male student being kneed in the groin by a female student, officials said.

The girl, who was not identified because of her age, was expelled for what her family called an act of self-defense.

The protest, staged on April 4, was the idea of boys who were angry over a Snapchat selfie posted from the boys' bathroom by a student who is transitioning, according to a statement by the Farbanks North Star Borough School District. The boys decided they would barge into the girls' restroom and take their own selfie "as a form of protest," the statement said.

One boy made it past the restroom door before getting kneed in the crotch by a girl inside, according to reports. Her parents told The Washington Post that the boy was blocking her from leaving and she defended herself.

The incident quickly went viral and became national news when state Rep. Tammie Wilson held a press conference to defend the female student. To other girls at the school, Wilson said, "If you ever feel threatened for your safety, whatever force you have to give, I will stand behind you. And so will your community. Not for those boys who were where they didn't belong."

To the Fairbanks Daily News-Miner, the legislator said, "Was she not supposed to protect herself? I said, 'Good for her.' I would have taught my daughter to do the same."

The female student's sister took to Twitter to say, "My sister was expelled for kneeing a guy in the" groin "after he was blocking her in the WOMENS bathroom."

The incident unleashed a viral controversy that mirrors public debate over whether transgender people should have their own private toilet facilities or be allowed to use the bathrooms for whichever gender they identify with.

The boys "protest" to barge into the girls' bathroom was just an effort to bully the transitioning student, many parents and students told the district.

But district officials said an investigation found no evidence the boys were threatening other students and that the male teens retreated as soon as the first boy was kneed.

Violence of any kind is not tolerated by school officials, the district's statement said.

The girl's family told the Post they will appeal their daughter's expulsion.

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