The warm spring weather has teens dusting off their summer clothes and forcing teachers and principals, bound by school dress codes, to bear down on those showing off too much skin.

In response, the tech-savvy Gen Y is turning to social media to protest against what many claim are sexist rules that seem to fixate more on teenage girls than boys.

A London, Ont., student encouraged her peers to wear ripped jeans and tank tops to school on Wednesday and post photos using #MyBodyMyBusiness after she was sent home for a similar outfit.

A day earlier, an Etobicoke, Ont., student started #CropTopDay after her school deemed her midriff-baring shirt inappropriate. Girls from other schools and cities showed their support by #StandingInSolidarity in crop tops.

The publicity has rekindled a decades old debate over appropriate school attire. And some North American schools have been turning to uniforms as a way to solve the subjective nature of dress codes.

But, while dressing everyone alike can make enforcement easier, it also poses challenges for parents and the students forced to wear them.

Uniforms 'raised the bar'

In Canada, while most public schools have a dress code, few require students to wear uniforms.

One recent exception is a public high school in Brampton, Ont., which introduced mandatory uniforms at the beginning of this school year.

Central Peel Secondary School students can now only choose some combination of a white or dark green, short- or long-sleeve collared shirt; a cardigan or pullover sweater; and black dress pants, shorts with at least a 20-centimetre inseam or skirt with a hemline at least 2.5 centimetres below the knee to wear to school.

Alexi Halket, 18, was told by an Etobicoke, Ont., school that her crop top was inappropriate. (The Canadian Press)

Parents repeatedly asked for uniforms, says Lawrence DeMaeyer, the school's former principal, who oversaw the start of the year-long pilot project. (He left in early 2015 to become the Peel District School Board's school support officer.)

Many parents felt the business-like attire would help kids focus on their schoolwork, he says.

"There's no question that with the school uniform we had a lot less issues with students dressing inappropriately," he adds. "It raised the bar way up."

Before, the most frequent dress code violation was students wearing revealing clothing. Now, violations centre on whether or not students are wearing the uniform.

About 90 per cent of students complied immediately, he says. Some slip up now and again, while a small percentage "spent their time trying to resist in every way."

DeMaeyer found that having to deal with the small resistance to uniforms "much more palatable" than having conversations about revealing fashion choices. Those are "very difficult" conversations for male teachers and administrators to have with female students, he says.

The school's uniforms will be re-evaluated at the end of the year, but DeMaeyer believes they'll stay.

Uniforms can be more expensive

"As a mom, it's easier for me," says Barbara Cruz, a University of South Florida professor of secondary education. She's had kids attend schools with no dress code, with a dress code and with a uniform — and the latter is her favourite.

"At the beginning of the year, I buy [my daughter] five days worth of school uniforms and we do the laundry on the weekend."

There's a lot of anecdotal evidence about the benefits of uniforms, says Cruz, who wrote School Dress Codes: A Pro/Con Issue​. She's interviewed many teachers and administrators who say students are more focused, better behaved and have higher attendance records and academic achievement when in uniforms.

They also say it's easier to spot a stranger at school when everyone is wearing similar clothes.

Laura Anderson was sent home to change by her vice-principal after showing up to school in ripped jeans and a tank top because the outfit failed to meet the London, Ont., school's dress code requirements. (Sophie McGregor/Facebook)

But, there's no empirical research to support these claims, she says, because it's hard to account for other variables when studying one aspect of a school. And, anecdotally, there are strong reasons to oppose dress codes as well, she says.

Some parents feel their authority over what their child wears is being usurped by the school when uniforms are mandated, she says.

Others find uniforms more expensive than regular clothes and a strain on the family budget as parents still have to buy regular clothes for their kids to wear after school.

Often, uniforms have to be purchased from one vendor at the start of the year, she says, which eliminates the potential of finding a good sale, shopping at a thrift store or using hand-me-downs from family members.

Uniforms also don't eliminate socio-economic differences in the classroom, as students can still find ways to wear costly jewellery or designer shoes, Cruz notes.

At the Brampton school, students are permitted to buy their bottoms from regular retailers as long as they are the right colour and length, DeMaeyer says. That reflects a compromise between what students and parents wanted during consultations, and means some kids can wear expensive Lululemon pants, which retail for about $100.

While Cruz finds uniforms easier and sees more schools in her state moving towards them, she doesn't necessarily believe they're the right solution to the recent dress code protests.

Instead, she'd like to see schools involve families and students in collaborative conversations to create more buy-in about appropriate clothing.

Students may even surprise schools and vote in favour of uniforms, she says, adding one of her daughters missed the convenience of her simple morning routine after graduation.

DeMaeyer, too, received positive feedback from students who say they find it much easier to get dressed in the morning now and felt less competitive about their clothing.

The majority of the students' parents also felt the uniforms have a positive impact, he says. "You have to create an environment where you're going to make as many people comfortable as possible."