An invite for a sixth-grade class' pool party last Monday had one Indiana mom very upset.

Jennifer Smith's son brought home the invitation, which was for well-behaving students, but the stipulation required for female students is what kept her from letting her son attend.

"All girls must wear a non-white T-shirt over their swimsuit," the invite said. (Similarly, a "no Speedos" rule was issued for boys, according to Babble.)

A feminist, Smith told the Huffington Post she was "kind of enraged by that" statement. She felt the message was a method of body shaming and not the appropriate message to send to young girls about their bodies.

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The instructions on the slip were "contrary" to what she's teaching her son, she said to HuffPost.

Rhoades Elementary School officials in Indianapolis said inappropriate swimsuits had been worn to previous parties, and the T-shirt rule was a way to circumvent that, according to Babble.

One district official told HuffPost the T-shirt rule was also a way to help families avoid having to buy another swimsuit.

After a heated email exchange, the district eventually said on the Thursday before the party that T-shirts for all students are optional.