Infants play key roles in adult-focused films

From “Baby Carlos” bonking his head on a cab door in “The Hangover” to Sacha Baron Cohen retrieving “Baby O.J.” at the LAX baggage carousel in “Bruno,” this year’s R-rated films appear to put tots through some pretty tough stuff. However, few things are more closely regulated on set than the treatment of babies, thanks to strict codes and union regulations.

According to California state law, babies (ages 6 months to 2 years) are allowed to spend a maximum of two hours in front of the cameras. The law also dictates that there must be a guardian, social worker and nurse on set when an infant or baby is working. Though not legally required, studios also often employ a baby wrangler to help keep a child in the right mindset.

Dawn Jeffory-Nelson, a wrangler who worked on “Lemony Snicket’s A Series of Unfortunate Events,” tries to find ways to make games out of tasks that need to be performed on a shooting day. “In ‘Lemony Snicket,’ the babies actually needed to be inside a cage for some scenes, so I had the cage that was going to be used delivered to where the babies were staying,” she says. “We played inside the cage with their toys, and we always opened the cage instantly if they ever felt uncomfortable, so the cage was a playhouse to them.”

With “Little Mongo,” the Down syndrome baby Mo’Nique pushes off her lap in “Precious,” it was director Lee Daniels’ niece who located the right kid. Usually, that task falls to the extras department.

“You’re really looking for a baby that’s stranger-friendly, who can go to anyone and be happy,” says Alex Morawec, owner of Major Minors Management. “Identical twins and backup babies are often cast to be sure that rules about time on set are followed.”

Baby Carlos was played by twins (whose names were omitted from “The Hangover’s” credits), for example, and Bruno’s African baby alternated between twins Chigozie and Chibundu Orukwowu.

Follow @Variety on Twitter for breaking news, reviews and more