Durban (CNN) Oscar-winning actress Charlize Theron was born and raised in South Africa, where she grew up around HIV and experienced people dying from AIDS. Now 40, she blames society -- not the infection -- for why the virus still persists.

On Monday, Theron took the stage before 18,000 doctors, researchers, activists, policymakers and heads of state at the official opening of the 21st International AIDS Conference in Durban, South Africa, and used the opportunity to share some hard truths.

"We value some lives more than others," said Theron, a UN Messenger of Peace and founder of an outreach project targeting South African youth affected by HIV. She acknowledged that something is "terribly wrong" when 2.1 million people continued to become infected with HIV in 2015, despite us "having every tool to prevent the spread of HIV."

She went on to voice something others might dare not.

"We value men more than women ... straight love more than gay love ... white skin more than black skin ... and adults more than adolescents," she said as the audience applauded.

In an interview with CNN, Theron discussed her experiences with HIV/AIDS and why she cares so much about ending the AIDS epidemic, particularly among teenagers, through her projects and promoting #GenEndIt , part of the UN strategy to "be the generation that end AIDS."

This conversation has been edited for clarity and space.

CNN: Before you left South Africa, did you have many personal experiences with the disease?

Theron: Yeah, it was constant. There was a period in my teenage years where that was the predominant conversation happening everywhere, in every household. My parents had a business, people weren't coming to work. People were dying, nobody knew why. Everybody was dying from TB [though some of them were clearly dying from AIDS].

There was great suspicion around all of it. There was much more information coming from America and from Europe than from Africa, ... I think culturally we hurt ourselves because we are a very conservative nation who doesn't really want to talk about certain aspects of sexual behavior or things like that and I think it hurt us tremendously.

CNN: Why do you care so much about HIV among adolescents?

Theron: Well, it's hard to be South African and not care because it's been so prevalent in our country. I think it would be hard to find a South African that hasn't personally been affected by the tragedy or a personal story or just witnessed the unnecessary deaths in this country.

And I think you know for me, that was always very much alive ... there was a part of me that really wanted to do something that I truly believed would be effective and efficient and so I had a real interest to want to know, you know, statistically, what was really happening, how disproportionate South Africa's infection rate was to the rest of the world, wanting to understand why, understanding the cultural situation that we find ourselves in and what is making behavioral change so much harder.

It became very evident to me that everybody in South Africa and the world knew that the epidemic took out almost an entire generation of parents. And when you then look at the youth of those kids that have been orphaned -- over 2 million children -- in a culture that finds talking about sex to be utter taboo, how are they supposed to find a way to keep themselves HIV-negative?

I want to be part of the generation that stops AIDS. I've seen people talk about how they stopped polio, that was a generation that came together and said, "Let's do this." I think in the AIDS community we've become so complacent in that, it's like we just plateaued ... We've completely neglected a whole young generation that is now highly infected.

CNN: When you come back home now and you go to where you grew up now, how does it differ?

Theron: I've witnessed a great change in communication and how young people are talking about it. Whether it's allowed back home, that hasn't, I think, necessarily changed. But going to them in a space where we're in their schools, their school environment, we're bringing a layer of health, sexual and reproductive health and education that they're not getting anywhere else. We're trying to bring it to them, to meet them in the middle somewhere, where they want it just as much as we want to give it to them. Nothing's being forced down their throats. You can't try to prevent one of those aspects without dealing with a lot of the other social situations that these young children find themselves in.

Other than vaccines and finding a cure, most funding goes toward putting people on treatment. That's completely valid and I understand that, but it's never how we're going to stop AIDS. It's hard to get people to invest in an age group that some of them find to be too impossible to reach ... I mean look, we were all teenagers at one point. Yeah, it's a very, very difficult age group to reach effectively, but it makes it even more the reason why we should, you know?

CNN: Do you feel like you see things differently because you're from here and you grew up in it?

Theron: Well, I feel like I know South Africans. I feel like I know our culture. I feel like I know what is taboo and how we function and what makes it problematic to work in the field that I am because of that. But if you look at the virus, this is a global virus and I think there are aspects to that that's just completely without borders, it's without gender, it's just people are globally affected by this in a way that we can all talk about, right? But I do think that when you're specifically working in a country like South Africa, you have to be able to be aware of the cultural truth of what people are raised in and believe in and how they function within their society.

CNN: What does it mean to you then, as a South African, that the conference has come here?

Theron: There's a part of me that, as a South African, I'm happy that our country can be supporting something like this and hosting something like this. At the same time, there's a part of me that wishes that it were not -- that we don't have to do this anymore.

We've had 21 of these conferences since 1985, I believe that we've slacked in many ways in actually stopping HIV once and for all. I think there are a lot of drivers involved in that, that have not really been truly addressed, that people are too scared to talk about [the inequality around gender, race and sexuality] ... I'm always excited about the possibility of like-minded people coming together and doing that. At the same time, it makes me question why we are still coming together and doing it.There are aspects in prevention and stopping AIDS that I don't think are fully addressed and I think, for me, I wanted to be part of this conference because I want to have that shared conversation with other people in different fields.

CNN: Is there a specific person that stands out that keeps you thinking about why you do this?

Theron: Well, there was a young boy in a sexual and reproductive health education class early on when I started working. I was kind of still finding my own way but he was incredible -- his story has always stayed with me through all of these years. I tend to cry when I talk about, so, it's amazing how long it's been affecting me this way, I think it was a mixture of reasons. I am South African and I am so aware, even as a white, privileged South African, that even within our community of privilege the idea of talking about sex or sexual preference or sexual identity or anything like that was just, nobody ever did that and nobody ever felt comfortable doing that.

I witnessed this 16-year-old boy in a class about female condoms raise his hand very, very proudly, in front of boys and girls, his peers, and asked if he could use a female condom for anal sex. Within that one question he stated a lot about himself that I had never witnessed in South Africa. It was very powerful for me. I'd never seen a 16-year-old boy be that proud or that confident to talk in that manner in front of his friends.

CNN: And what was the response of the people around him?

Theron: We didn't know. Isn't that incredible? We all kind of looked at each other and you know, no one's ever asked that question and you don't ever want to give inaccurate information, so you always want to watch what you tell them. I got on a phone with a friend who works side by side with us, I think of him as a great educator ... he is a very well-known South African comedian, Pieter-Dirk Uys, and I called him. He's also openly gay. I said "Pieter, can you use a female condom for anal sex?" and he said, "Of course darling, of course you can!" [Female condoms are We didn't know. Isn't that incredible? We all kind of looked at each other and you know, no one's ever asked that question and you don't ever want to give inaccurate information, so you always want to watch what you tell them. I got on a phone with a friend who works side by side with us, I think of him as a great educator ... he is a very well-known South African comedian, Pieter-Dirk Uys, and I called him. He's also openly gay. I said "Pieter, can you use a female condom for anal sex?" and he said, "Of course darling, of course you can!" [Female condoms are not currently licensed f or use during anal sex and according to the Centers for Disease Control and Prevention , evidence for their effectiveness does not yet exist.]

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But it just, it moved me, because, you know, you think sometimes the hill is too high, the idea of stigma and the taboos of behavior and how people have lived for so long believing one thing, misconceptions about HIV and AIDS, all of that stuff is very frightening. It feels like that mountain is just too high to climb.

Then when you experience something like that, it reenergizes you to believe that it's not impossible.

That boy changed it for me, very much.