A U.K. politician is fed up with needlessly gendered kids’ products.

On Tuesday, Labour Party councillor and father Joshua Peck tweeted a photo of a space-themed lunch box from retailer John Lewis. The item’s tag indicated that it was a “Boys Space Print Lunchbox.”

Hey @johnlewisretail. What is it about this lunchbox which makes it unsuitable for my daughter? Too sciencey? @LetToysBeToys @PinkstinksUK pic.twitter.com/ztLscadDsB — Cllr Joshua Peck (@CllrJoshuaPeck) November 1, 2016

”Hey @johnlewisretail. What is it about this lunchbox which makes it unsuitable for my daughter? Too sciencey?” he tweeted.

The comment prompted a long Twitter discussion, in which parents shared photos of their science-loving daughters and called for retailers to just #LetToysBeToys. Peck, who has a 4-year-old daughter, also shared a photo of a John Lewis “Boys Pirate Ship” product listing, which he tweeted in 2013 with a similar message.

“As the father of a young daughter, I’m constantly shocked at the messages we send to children from the earliest age about who they should be and how they should behave according to their gender,” Peck told The Huffington Post.

“Children learn everything they know from watching what adults do and say, and when we call girls bossy, say boys shouldn’t cry, or talk about boys’ jobs and girls’ jobs, we limit their potential hugely,” he added.

Speaking from his personal perspective as a parent, Peck noted, “I want my daughter to feel able to do what she wants to do ― be a mother, a fire fighter or a scientist ― based on her talents and ambitions, not what society thinks is appropriate for her to do. It’s really not that radical, and it’s sad that it still needs saying.”

While Peck acknowledged that major retailers like John Lewis have made great progress on this issue in recent years, he said it’s still important for people to call out products that promote harmful gender stereotypes when they see them.

John Lewis representatives have taken note of Peck’s tweet and maintain that it was simply a matter of erroneous labeling. A spokesperson for the company told HuffPost UK:

“We’re really sorry that a one-off labelling error meant that our Space Print School Lunchbox was marked incorrectly. We’re looking into correcting these labels as soon as we can. We understand the importance of providing girls and boys with as much choice as possible, and in recent years we’ve changed our childrenswear and toy ranges so that they’re not categorized by gender.”

Whether or not the label was an error, Peck is still pleased that the tweet provoked an important discussion. “It’s easy to use words without thinking about what message they send to our kids, so its great to break that down, even if just by the tiniest bit,” he told HuffPost. “I also hope retailers will realize there are lots of people out there who really care about this stuff and keep working to improve.”