With more single-sex schools going co-ed, what is the evidence for gender-segregated education?

Some experts said said there wasn’t much evidence to support improved academic outcomes were a result of sending a child to a single-sex school. (ABC News: Claudia Long/Canva)

Sydney mother-of-two Leanne Bergan is a strong advocate for public education and co-ed schooling.

Nevertheless, her son Jack graduated from Randwick Boys High last year and her daughter Bronte is sitting her HSC at the equivalent girls’ school, in what Ms Bergan says has been a “great school experience”.

“It wasn’t my choice to send them to a single-sex school,” she said.

“But ultimately I wanted them to be in their local community school because this is where we live and where their friends are.

“I think it’s served them pretty well. My son wasn’t a completely academic child, but I felt like he had an opportunity to learn.”

But come next year, the large eastern suburbs high schools will merge to become co-ed, something Ms Bergan supports despite her children’s single-sex schooling success.

“I think there is probably more opportunity for broader curriculum choice when you have a co-ed school,” she said.

“I know of some classes that couldn’t be run at the boys’ school, for example, because they didn’t have enough students, and that’s disappointing.”

Still, she acknowledges other parents are “anxious” about the change, particularly at the girls’ school where many students had enrolled from outside the zone.

“There just was this shock that, you know, they didn’t want to lose the culture.”

Emotions have also been running high at all-boys Sydney school Newington College, as parents and alumni protest its decision to welcome girls from 2026.

But what does the evidence say about single-sex versus co-ed schooling?

We asked education experts, advocates and a neurologist to break it down.

Are single-sex schools better for girls?

A persistent idea around schooling is that single-sex education is of particular benefit to girls, but University of Sydney Professor of Education Helen Proctor said there wasn’t much evidence when it comes to academic outcomes.

That’s because a student’s class background is far more influential than whether they attend a single-sex or co-ed school, she said.

“There’s a very strong statistical correlation, stronger than it should be, between social class and academic achievement,” she said.

“There’s a myth around that co-education is better for boys and single-sex is better for girls, and really you can’t pin down the evidence but it’s one of those widely held common-sense myths.”

Here are some of the key studies that have looked at the issue:

• A 2014 meta-analysis of 184 studies representing 1.6 million kids in 21 countries concluded there was “little evidence of an advantage” between single-sex or co-ed schools, based on the highest quality studies
• A 2022 review of nearly 5,000 Irish teens found no significant difference in reading, science and maths results once results were controlled for factors like socio-economic background
• In 2017 the Australian Council for Educational Research compared NAPLAN data and found that, on average, single-sex schools showed no greater improvement over time than co-ed schools

Advocates often argue single-sex schooling means girls are more likely to study science, technology, engineering and maths (STEM) subjects.

But when researchers Helen Forgasz and Gilah Leder looked at 17 years of Victorian data, they found boys and girls alike were more likely to study maths and science in single-sex schools, and suggested socio-economic status, class size and teacher quality might have been the main drivers.

Professor Proctor agreed other factors were at play when assessing why single-sex schools performed well.

“A high proportion of [single-sex schools] are very elite or wealthy schools or academically selective public schools,” she said.

“There are some older, public high schools that are girls’ schools, but they often tend to be in quite middle-class areas with middle-class catchments, so that’s another reason for doing well.”

Proponents believe that while academic results may be the same, single-sex environments allow girls to develop more confidence.

“They feel like it’s a really safe space for them, that they do feel confident about stepping up and speaking out and having a goal and participating and all of those things,” said Loren Bridge, regional executive director Australasia for the International Coalition of Girls Schools.

“Academic results are just one part of a good education and I would really emphasise that for girls, it is about the social and emotional well-being.”

Ms Bridge also pointed to OECD data which showed those in single-sex girls’ schools were less likely to experience bullying than those attending co-ed schools.

A 2021 survey of more than 9,000 Australian adolescents led by Dr Terrance Fitzsimmons found that single-sex schooling appeared to improve girls’ confidence, but noted this could also reflect the fact the students tended to come from privileged backgrounds.

And in 2014, ANU researchers found that undergraduate female economics students placed in single-sex groups were more confident in taking a risk than those placed in co-ed groups.

Do boys and girls actually learn differently?

In short, no, according to neurologist Lise Eliot from Chicago Medical School of Rosalind Franklin University.

“There’s no truth to the claim that boys and girls learn differently,” Professor Eliot said.

“Girls tend to outperform boys in reading and writing, but in terms of how children learn to read and how children learn to write there’s no difference.”

Structurally, Professor Eliot said the idea of a “male brain” or a “female brain” just did not stack up, based on her 2021 review of three decades of research.

And on maturity, Professor Eliot said girls did go through puberty earlier than boys but it did not have a huge impact on learning.

“If you look within a classroom among a group of boys and girls and different measures, either of achievement or even of maturity you’ll see, again, a lot more overlap than separation among them,” she said.

British neurobiologist Gina Rippon agreed and said the idea that girls and boys brains were different should be challenged.

“The key thing I’m always really anxious about is the idea that if you put all boys in a classroom, they will all learn the same way,” she said.

“You’re actually under-supporting probably about 50 per cent of those boys because they don’t learn in that way, and similarly with girls, and I think that’s really important.” 

While boys and girls may not learn differently, advocates of all-boys education maintain they mature at a different pace.

Single-sex boys’ schools could be better-equipped to account for that difference, according to Tom Batty, executive director of the International Boys’ Schools Coalition, a group of more than 260 schools across the world.

“If you’re a family and you’re thinking of sending your son to a co-ed school, a very fair question to ask would be, ‘on average boys and girls develop with different times and different rates … what are you doing about it in your school?’,” he said.

While data is limited, he cites Dr Michael Johnston’s longitudinal research from New Zealand showing boys in all-boys schools go on to have better outcomes than those from co-ed schools, the effect being stronger among disadvantaged children.

Dr Johnston noted it wasn’t clear whether the gender composition was the cause of the improved outcomes: “For example, a reputation for excellence may cause aspirational students to tend towards single-sex schools”.

Mr Batty said relying solely on data to make a decision was overlooking the more important aspect of choosing a good school.

“Good teachers that like their areas of interest, want to be involved in areas of the school beyond their teaching areas, form great relationships with the kids, that the school is well run, it has good leadership, it’s well resourced,” he said.

“Boys are hugely relational and they learn their teachers before they learn a subject.

“I would contend that for many boys, they would be better suited at a good boys’ school than a good co-ed school.”

What do we want out of the education system?

Some academics argue we should look beyond whether single-sex is better or worse and consider whether the education system should be designed around the key values we want to promote among young people.

George Variyan, an education lecturer at Monash, has studied how sexist attitudes can manifest in private single-sex boys’ schools.

In a 2021 study he interviewed 33 female teachers at three elite boys’ schools and found they were exposed to these attitudes in the classroom.

“It might be the ways in which students subvert a teacher’s authority in classrooms by sexualising them or by appealing to norms of male authority,” he said.

Dr Variyan said schools could do a lot to address these issues and educators were doing their best, but often school traditions and cultures hampered these efforts. 

“It’s not just about single-sex schools, these are typically very privileged schools,” he said.

“Right now we are seeing increasing diversity, increasing nuance in understanding of gender, that I don’t think it’s particularly sustainable that we are gender segregating our schools.”

As for girls’ schools, Professor Proctor said while there wasn’t strong evidence that single-sex environments alone reduced classroom disruption or increased confidence, that didn’t mean gender wasn’t a factor in the community at all.

“I think across single-sex and co-educational schools that people have to be mindful that gender is a really strong social force, and it does shape the way people think about themselves and it shapes the way they are treated,” she said.

“We don’t want to be imposing narrow, restrictive gender stereotypes on young people … we want to encourage them to be the people that they want to be and to express themselves in all sorts of ways without having to conform to narrow understandings of what it means to be a girl, or what it means to be a boy.”

Leanne Bergan agrees.

“I do understand how some people see single-sex as being preferable for them, but I just think it’s not in step with everything else: primary school, university [and the] workplace,” she said.

Got a story to share? Contact the ABC’s Specialist Reporting Team