Ashton Kutcher has to stop his daughter "killing herself" on a regular basis.
The 38-year-old actor admits 17-month-old Wyatt - who he has wife wife Mila Kunis - is completely fearless and has no concept of what could be hazardous.
He said: "She's actually crossed that threshold. That first year, you spend just trying to keep them alive. And then after that, you actually hit a point where your job is to keep them from killing themselves...She tries to kill herself on a regular basis.
"Like, she doesn't realise that's a cliff and that could be dangerous. She'll just jump off the thing. She don't know yet. You'd think that they would come with instincts around fire and large falls, and they don't. I don't understand how prehistoric man lived. How did they in the jungle not jump off waterfalls and just know?"
The 'Two and a Half Men' star also spoke about his secret wedding in July 2015, admitting it took a "ninja effort" to keep the nuptials under wraps.
He told talk show host Ellen DeGeneres: "It was a ninja effort. We really didn't want [paparazzi] helicopters at our wedding and it's a legitimate concern. I was, like, posting things on social media that were in different locations to avoid it.
"We didn't want to be screaming our vows at each other and being like, 'Forever! Did you say never?' We went really under the radar with it."