When Charlize Theron overheard a gay teenager inquiring about using a condom, the award-winning actress knew she had finally made some progress in fighting AIDS in Africa.

The U.N. Messenger of Peace opened up on Monday at the Mashable Social Good Summit about her decades-long commitment to tackling the HIV/AIDS epidemic. Theron became emotional while noting how the once-taboo topic, which incited fear in her home in South Africa, is now openly discussed among at-risk youth and can feasibly be wiped out by 2030.

Theron realized the stigma surrounding AIDS had finally started to subside eight years ago, while she was helping to conduct a workshop in Africa. After a volunteer had demonstrated a female condom to the class, a 16-year-old boy asked if he could use it for anal sex.

“I was so moved because that never happened when I was growing up,” Theron said while tearing up during the Mashable panel. “People didn’t feel safe to talk in that manner. I know that that boy is alive, because he felt safe enough in that environment to ask a question.”

“That’s when I knew we were starting something that was going to turn the needle,” she added.

This year’s two-day summit is honing in on how technology and new media will help the world reach the U.N.’s newly adopted goals to end injustices around the world. One of those 17 goals includes ending AIDS in the next 15 years.

And experts agree that it’s actually feasible.

Since 2000, the number of new HIV cases has dropped by 35 percent, from 3.1 million to 2 million, according to UNAIDS.

That decline has been attributed to a number of factors, including greater accessibility to antiretroviral drugs, community outreach programs and mobilizing activists worldwide.

But to continue that momentum, Theron and other activists say that the world needs to lend more resources to grassroots groups.

“The people who are doing the good work are the small, grassroots organizations who are on the ground that nobody is talking about, nobody is supporting,” Theron said. “It’s the people living in the villages with those young girls, with those adolescents who are at high risk.”

Theron, who founded her eponymous foundation to keep young people in Africa safe from AIDS, noted that it’s these groups who are most attune to the obstacles and inequality and educational issues that young people there face.

And while Theron is emboldened by the progress being made in Africa, she’s also concerned about how the world may still be too “complacent” about the virus.

While there have been significant drops in overall AIDS deaths, it remains the leading killer among adolescents in Africa and the second leading cause of death among all adolescents globally.

Theron hopes that by keeping the conversation going, she’ll be able to help reinvigorate activists across the spectrum to continue to keep AIDS at the forefront of the activism agenda.

“That should be something we should all be concerned about,” Theron said of how AIDS disproportionately affects women. “That affects me. That affects you. That’s not just an African problem. That’s not just as Asia problem … that’s all of us.”

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