The em dash has long been a favorite punctuation mark of writers everywhere. This lengthier dash can replace a comma or a colon. It’s also sometimes used to sum up info at the end of the sentence, to encase parenthetical info within a sentence, or to emphasize a point. To know an em dash is to love it, but according to Gen Z, it’s often a dead giveaway that someone’s writing came straight from ChatGPT.

This so-called “ChatGPT hyphen” is getting a lot of attention at the moment, according to podcaster Daisy Reed, who spoke about it in a recent episode of the LuxeGen podcast alongside co-host Sapna Rao. Reed pointed out that the clothing brand PrettyLittleThing recently announced a rebrand on social media, and the post was positively teeming with em dashes. The top comment under it read, “Including the ChatGPT hyphen [in this] is insane.”

According to the hosts, em dashes typically include a space on either side, which is true if you’re using AP style — a go-to for major publications. For another example, look at the sentence “When her best friend arrived — a half-hour later than expected — Liz’s party finally began” versus “When her best friend arrived—a half-hour later than expected—Liz’s party finally began.”

While spaces aren’t required when using em dashes, Reed said she’s noticed it feels very ChatGPT-coded to leave them out. The AI app seems to omit the space. As a result, “people are being called out that they are using ChatGPT,” she said.