This morning I checked my watch and apparently it’s 1952. At least according to a damning new report about gender inequality in Australian girls and young women.

Plan Australia and Our Watch surveyed 600 girls aged 15 to 19 to tell us how they feel about gender inequality.

Nine out of 10 say they are not treated equally to boys. Half feel they are not valued for their brains and opinions over their looks. And five out of six girls believe that they are not given the same chances in life to get ahead as boys.

Gender inequality is a problem, say 69% of young Australian women Read more

Unfortunately, every day, in a million small ways, girls are still not as valued as boys.

Take for example, events of the past few days.

Donald Trump’s appalling and completely inexcusable account of casually sexually assaulting women were not surprising given his track record.

What was surprising, however, was the overwhelming response from girls and women worldwide, who were prompted by author Kelly Oxford to share their first account of assault using the hashtag #notokay.

Within 24 hours, this hashtag had exceeded 10m impressions on Twitter. At one point, she was receiving 50 tweets a minute.

Laurenn McCubbin (@laurennmcc) @kellyoxford I was 10, he was my babysitter. Told me he was training me for boys when I got older.

A sizeable majority of these tweets were from women, who were just girls when they were assaulted – often by a stranger, in a public place.

“I haven’t met a woman who doesn’t have a story of abuse. It shouldn’t surprise me that this extends beyond the women I am able to meet. Anyone denying rape culture, look at my timeline now,” Oxford said.

This outpouring of experiences of harassment and abuse absolutely legitimises the power imbalance that plagues our society today. And gender inequality lies at the very core of it.

Today is International Day of the Girl. It’s time for all of us to start questioning.

Why, in 2016, do girls and young women still fear for their safety after dark, cop harassment and abuse on public transport and are targeted on the streets?

One of Plan International’s youth ambassadors, at 16, was one of these young women. In her own words, she describes a disturbing incident.

My friends and I were walking on Church Street one Sunday. A group of three guys came past and one of them grabbed my butt. It really hurt. I turned around and said ‘get off me, don’t touch me’. He just said to me ‘I know you want more’. It left me feeling really horrible and shaken up. I was crying. Being wolf whistled or cat called on the street happens to us a lot. I’ve tried stopping them, but they always say: why are you so upset about it, they say, it’s a compliment?

Attacks like this happen to girls every day. But whenever we attempt to have a discussion about this abuse of girls – overwhelmingly perpetrated by boys and men – the response is the same.

Don’t be unfair, stop singling us out, women are just complaining, they’re attacking us, it’s all just a conspiracy against the patriarchy. And by the way, didn’t we already deal with this feminism stuff in the 1960s?

Let me say from the outset that I believe most men and boys are inherently good and respectful of women. But for those who aren’t, their actions are hurting all of us.

These are the boys who are talking about girls like objects. The boys who are running photo-sharing rings of underage girls and rating them on their attractiveness. They are slut-shaming young women, hollering out on the street, acting with disrespect, targeting girls to humiliate and shame them.

Our youth ambassador also remembers being “rated” at only 13 years old:

A guy at my school made a website with photos of the girls from my year level to rate us out of 10. I was rated a 5/10. My school said they were dealing with it. They told us that these accounts would be taken down, but the original accounts are still there, and new ones are being created all the time.

It’s sad and shocking that this is happening to our girls. But it is an awful truth shared the world over.

Girls are the most marginalised group on the planet. They are the most invisible, the most unheard, abused, controlled and deliberately oppressed so they cannot get ahead.

Globally, the situation is dire: girls and young women make up 70% of out-of-school youth and 82 million girls each year in developing countries are married before their 18th birthday, robbing them of a future.

When we talk about gender equality, it’s natural to think of these issues referencing women, but in fact, it starts early.

Stop judging women on how they look – it is damaging our children | Laura Bates Read more

More than half of the girls and young women we surveyed (56%) said that their brothers or boyfriends only sometimes or seldom did their equal share of housework.

In fact, a UK study of 1,200 kids and their parents showed girls were getting 13% less than their brothers.

Studies like these shed some light on why, 114 years after women got the vote in Australia, girls are growing up thinking they shouldn’t pursue their dreams because it’s just not worth it.

The truth is, holding girls back is hurting all of us. No society can thrive if half its population can’t achieve its potential.

We should all be worried about the findings of this report and asking what we can do – as parents, teachers, politicians, friends, sisters and brothers – to make the world a more equal, welcoming and supportive place for girls.

Today, girls all over the world are standing up and having their voices heard. Plan International’s Girls Takeover campaign sees more than 200 girls worldwide in charge of political offices, news networks, ministries, police stations and schools.

In Australia, we have partnered with Facebook to mark International Day. I invite all Australians to temporarily change their profile in solidarity with girls by visiting our Because I am a Girl campaign page.