While appearing on Zane Lowe's Apple Music show Tuesday, the singer revealed one of her sons had recently welcomed two children.
"My youngest son just had two babies," Sia, 44, said. "I'm just immediately horrified. No, I'm cool. They call me Nana. I'm trying to get them to call me Lovey, like Kris [Jenner]. I'm like, 'Call me Lovey.'"
The pop star continued to talk about her growing family and opened up about her decision to adopt two Black boys who were "aging out of the foster care system" last year.
"I'm a little bit jaded now after investigating the foster system as much as I have done in the last year," Sia said, describing foster care as a "completely corrupt" system. "It's failing us. Not in my experience, in my sons' experience. They've been in 18 different locations in their 18 years."
"Started out as a pretty massive roller coaster. They told me one thing, I discovered another," she continued. "But I just stayed really like a kind of Al-Anon Ninja. I just kept really strong boundaries. I would say, 'You could do this, or you could go back to where you came from,' which is not a nice life. It's not a good life, and I'd say, 'I'm doing this because I'm your mother. I love you. I have no other agenda other than the fact that I love you.'"
The "Chandelier" singer said she told her sons: "I don't want to see you in prison. I don't want to see you as that 5 percent that's in prison with your history and the color of your skin. I don't want to see you as that 5 percent that ends up in prison for life. I don't want that for you. I want something different. There is something different for you. If you just trust me that... I, in this one case, I know better."
Sia added that both of her adoptive sons had suffered "condition and complex trauma" from being in foster care, prompting her to get them the help they needed.
"Both of them have been through trauma programs since I adopted them," Sia told Zane. "One recently came out, and he's just blossoming and is the light of my life. I love him so much. And the youngest is right now in trauma processing."
"I really pray that he can manage because it took me until I was 41, I think, to deal with my early developmental trauma," she continued. "I don't want that for them, but you can't force anyone. Trauma has to come out when you're in a safe environment when you're ready -- psychologically ready. So, I'm just trying to do my best for them."
While discussing the topic of white privilege and the ongoing Black Lives Matter protests, Sia broke down, "I'm going to cry."
"I'm embarrassed that it took me to adopt two Black sons to really understand what they go through on a daily basis...There are things to do. We can actually act, and we can actually try and get justice for Breonna Taylor and Elijah McClain."
"I've very scared for my children. I love them so much, you know?," she continued through tears. "I've only experienced white privilege and I know that now. I am fully aware of how much I've experienced white privilege, and now I have these two Black sons who tell me how it really is."