But, for Marson, reducing the human toll of sexual violence starts in the classroom, not a courtroom.

In a time of helicopter parenting, cyber sex, and now #metoo, sex ed has become a minefield for teachers to navigate. Studies suggest lessons haven't moved far beyond the old condom and the banana routine in their relevance to students, and Marson warns misplaced moral panic is still blocking much-needed reform.

This year, conducting research as part of a Churchill Fellowship, Marson spent months learning first-hand from the world's top sex ed programs in the UK, Ireland, Canada, Germany and the Netherlands. She's now leading the ACT government's implementation of recommendations from the Royal Commission into child sexual abuse, including the creation of new failure to report offences.

Marson says teaching intimacy and consent to children early could be like a vaccine against the scourge of sexual and domestic violence.

"It's not always going to stop it, of course, but it's a defence," she says. "It's arming kids with an understanding of their boundaries, what's appropriate, how they should treat people. And they'll have that understanding their whole lives, at university, in the workplace."

As one nine-year-old in the UK told Marson: "If someone asks you to do something, you need to know what to do if you're uncomfortable."

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Scores of studies around the world have now backed intimacy and consent education as a harm prevention tool. For her own honours thesis, Marson compared the offence reduction capability of the criminal justice system with that of prevention education and arrived at a sobering conclusion - long-term, educators could have more power than judges in stopping sexual assault.

"Of course the law is still so important for victims to get justice and keep people safe, but we haven't been looking at the other end of the scale," she says.

"I've had cases where people have said they wished they'd been taught this stuff.

Education is so often seen as the great liberator but when it comes to sex, suddenly this is something someone is expected to learn by osmosis.

"I certainly wasn't taught the skills I needed at school to deal with the harassment and situations I found myself in, most of it when I was still a teen. And kids are still having similar experiences."

Unfortunately, Marson says, most of the successful sex ed programs around the world only arrived in classrooms after long and bitter campaigns fought by educators.

"It took 30 years of lobbying in the UK to get the reforms through in law," she says. "You almost need a public health campaign to counter all the misinformation."

In Australia, reform - such as Victoria's evidence-based respectful relationships curriculum (RRE) - has already been accused of sexualising children. The state started rolling it out just as concern about the LGBTIQ anti-bullying program Safe Schools reached fever pitch during the 2016 same-sex marriage debate.

And last year, Prime Minister Scott Morrison famously declared that one of the Victorian RRE lesson plans - which involved role-playing a bisexual woman having casual sex - had made his skin crawl.

"People say it's teaching kindy kids about masturbation and stuff that's not true," Marson says.

"It's a very emotional issue, people play on fear but this kind of education is age-appropriate. The young ones might be asked 'is it ok to keep tickling someone if they ask me to stop?'"

She stresses good sex ed is about good access to information. While families might put their own values on content, children still have a right to know the facts.

"Research shows young people are less likely to have a negative sexual experience if they know this stuff," she says. "If anything, they tend to wait longer to have sex."

Consent education was also a recommendation of the royal commission, which condemned a culture of secrecy and shame in many of Australia's institutions.

The term 'respectful relationships' has since found its way into the national curriculum, but in most states, including the ACT, experts say it remains adhoc and brief, mostly delivered in one-off workshops. Many practitioners, such as UK sex educator Lynnette Smith, say it needs to start much earlier.

"People always say to me: 'you can't teach 12 or 13-year-olds about consent!' and I say 'no you can't, because it's already ten years too late'," she said.

While some suggest carving that pesky s-word out of program titles altogether will put minds at ease, Marson says transparency is important.

"We can't keep shying away from the word. We've got to normalise sex, it's healthy, it's part of life."

In Germany, Marson says sex-ed is deliberately kept separate from violence prevention to encourage positive discussion of sex as well as "what not to do".

Amid calls from experts for clear reporting avenues and sexual violence policies in schools, Marson's work also underlines the need for more sex ed training and resourcing.

"It's not just Bob from geography running it. This is difficult subject matter and teachers need support to get it right, governments need to invest in this.

"But this is about keeping kids safe. We know it works so what are we waiting for?"