"If you tell a young boy to Google masculinity or go to TikTok or YouTube, he's going to find a lot of nasty content," says the leading research director, institute founder and gender expert.
"You've got to be tough; don't show feelings.
"When we go to schools, boys come to us and ask, "Am I toxic? Am I a disease? Am I the problem? Am I a monster?"
They were the kinds of interactions that inspired his latest project, according to the Brazilian co-founder of Papo de Homem, which translates to "man-to-man conversation".
Over a week in the mountains, the initiative involved teaching 11 diverse boys a curriculum based on research about what they need and what girls want them to change.
Australia certainly isn't immune to the problem, with a 2025 survey conducted by The Men's Project showing as many as half of the nation's males aged between 14 and 18 are influenced by talk of disdain for femininity and rigid concepts of manhood.
"What our data shows is seven out of 10 boys want to know how to treat all girls and women with equality, not violence," Mr Valadares told AAP.
"And they're saying, when we sit down with them, 'we don't know what to do'."
Both conservative and progressive Brazilian families were spoken to as part of designing the program, which included sessions on how to be emotionally balanced, responsible and respectful.
"If I'm teaching responsibility, I'm going to talk about care, consent; about how to be healthy, take care of my family, of the house," Mr Valadares said.
"If I'm talking about respect, I'm going to talk about race, gender, sexual orientation."
Earlier this week, he presented a documentary on the project, Dreaming the Men of the Future, at the international Mencare Changemaker summit in Rio de Janeiro, also attended by AAP.
Mr Valadares, who is open about being a reformed aggressive man himself, was hopeful the event would mark a turning point in how gender inequality had been addressed in the past.
"There's just so much history of pain that men have caused to women and girls," he said.
"And for the first time, in a broad sense, people are stepping away from the idea that working with boys and men would take something away from working with girls and women.
"Because from our perspective, caring for boys means caring for girls."
Survivor and advocate Daniela Ligiero, who was raised in Brazil and the US, said caring for boys and their experiences of sexual abuse was an important factor.
"One in five girls globally experience sexual violence before their 18th birthday, and one in seven boys," Ms Ligiero, president of Together for Girls, told AAP.
However, she said the average age of disclosure for men was 56, and 75 per cent never tell anyone.
Ms Ligiero said ending violence against women and girls cannot be achieved without honouring the experience of boys and men, and inviting them to become part of it.
"We can't expect men to care if we're not caring for them when they experience something as horrific as sexual violence," she said.
"There's a lot more we have to do around thinking about how we support and respond to boys who are victims of sexual violence, if we care about gender equality.
"There's an entry point there because there are also cycles of violence where a lot of these boys can also grow up to perpetrate."
AAP travelled to the conference with the assistance of the Minderoo Foundation.
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