Fashion norms are becoming more fluid these days; what was formerly particular to men or women is now open for interpretation. However, there is one minor feature that continues to distinguish men’s and women’s clothes, and some historians believe it is a centuries-old practice rooted in gender inequity.

When you next button your shirt, look at the placket, the reinforced fabric where the button meets the buttonhole. If you have access to clothing from the opposite gender, examine it closely to see if you can tell.

Women’s buttons are usually on the left, whereas men’s are on the right.

Over time, we have forgotten the precise roots of the unique opposite-button design, although specialists offer several suggestions.

Lady’s maid

One of the most frequently acknowledged justifications dates back to when affluent ladies did not adorn themselves. Upper-class ladies frequently used maids to assist them in getting dressed, and because most people were right-handed, buttons were put on the left to make it simpler for the maid to attach them.

“When buttons were invented in the 13th century, they were, like most new technology, costly,” Melanie M. Moore, creator of the women’s fashion business, told Today. “Back then, wealthy women didn’t dress themselves; their lady’s maid did. Because most individuals were right-handed, someone standing across from you had an easier time buttoning your dress.”

Meanwhile, males, who often dressed themselves, had buttons on the right, which was more convenient for a right-handed individual.

I am ready for battle.

Other academics believe men’s attire was tailored for combat.

Historically, many men carried weapons (such as swords or pistols) and needed convenient access. According to Chloe Chapin, a fashion historian, having buttons on the right side made it easier to unbutton jackets or coats while keeping the dominant hand free for action.

“I think it’s important to question which time we’re talking about,” Chapin, a Harvard PhD student in American studies, said. “But generally, we can trace many elements of men’s fashion back to the military.”

Women’s fashion, of course, did not consider combat functionality; therefore, the left-side buttons remained.

Masculine twist.

Chapin proposed another idea for why women’s dress began to include more masculine aspects in the 1880s.

“It was trendy for women’s attire to resemble traditional male styles. However, it was unlawful in many locations to dress like a man in public, so having a different buttoning pattern may have proven that you were wearing female clothing,” the historian explained.

Gender inequity.

In 1894, British sexologist Havelock Ellis claimed in “Man and Woman: A Study of Secondary and Tertiary Sexual Characters” that women’s clothing buttoning right to left indicated that women were considered physically inferior to males. He said that women had lower motor skills and lacked the “rapidity and precision of movement” of men, who, unlike women, did not need help getting dressed.

‘Button differential.’

People are only now recognizing what The Atlantic refers to as the “button differential,” despite this minor design element being present for years.

“It is a relic of an old tradition that we have ported, rather unthinkingly, into the contemporary world,” the journal argues.

The internet community is astonished.

One Reddit member writes, “I was today years old when I learned that women’s shirts have buttons on the left side!” And a second replies, “I just discovered that shirt buttons are on the left for ladies and right for me. Wtf!!!!”

Others shared their thoughts on the centuries-old practice, mired in gender inequality, that still influences fashion today.

“Ah, the big gender split—because, centuries ago, ladies needed assistance getting dressed, while males were supposed to fend for themselves.” Fast forward to today, and we’re still tying up old traditions,” tweets one person.

A second Redditor adds, “Zippers, too, usually!”

Some firms are now contesting gendered button placement, but most garment companies continue to use the left-for-women, right-for-men guideline.