Studies show that up to 74 percent of mothers and 70 percent of fathers show preferential treatment toward one child. Despite research showing that a favorite tends to be the youngest of two children, this aunt claimed her brother’s favoritism toward his oldest child has caused a full-on family rift.

Although only 10 percent of parents admit to having a favorite child, according to research by YouGov, these parents made their stance extremely clear, the aunt wrote in a popular online post that has sparked intense reactions online.

Under the name u/mano_mama3510, the aunt explained on the popular subreddit “Am I the A**hole” that her 12-year-old nephew, Oliver (all names have been changed by Newsweek), is “entitled” and “quite spoilt” by his parents, who show favoritism toward his 9-year-old sister, Amy.

“Now, I’m usually very strict when the kids are with me for the weekend,” the aunt wrote. “Oliver is usually on his best behavior. Oliver’s birthday was yesterday. Amy had a spelling bee last week and she got first prize. Her parents brushed it off but I was very happy for her because she spent hours learning each word and I was very proud.”

The aunt said she purchased her nephew a birthday present and her niece a congratulatory present for her win, a stuffed animal. However, after arriving at the birthday party, she discovered her niece had been grounded because of a sibling argument.

During the argument, Oliver destroyed the stuffed animal, the aunt said online. After reacting with a “temper tantrum,” Amy was grounded after being made to pick up pieces of the toy and throw them away.

“I was furious and refused to give Josh his birthday present, telling him he didn’t deserve it for being mean to his sister,” the aunt wrote. “I also told off my sister-in-law and brother, [saying] that they’re growing insanely cruel towards their young daughter. Now my family is pissed that I refused to give Josh his birthday gift.”

Reddit users backed the aunt for her decision about Amy’s present and aimed their anger at the parents.

“Make sure you let her know that she has family that does love her and cares about her because she is likely to need that support as she grows. Be ready to be put at a distance and ready to support her when you can,” advised one user.

“Wish you could adopt the girl instead. Poor girl. Maybe when she’s old enough that she can leave home without authority forcing her back she could come live with you,” added another.

One user agreed, writing: “Destroying her stuffed animal was sadistic. Beyond cruel. That she gets punished and excluded from a family event because she got upset about her possessions being destroyed?…whoa…that’s a whole other level. My hope is that you stick around for her. She’s going to need someone to let her know this isn’t okay. Glad you’re in her life.”

The aunt said in an update that she picked up her niece from the family’s home and offered to look after her for a few days—“if she’s being so rude to her brother”—in order to “get her out of there.”

“I got her a massive teddy bear which she’s keeping in my house and I took her out to get McDonald’s so she’s smiling. But I am looking for a more permanent solution,” the aunt said.

Newsweek reached out to u/mano_mama3510 but was not able to verify the details of the case.