Lawmakers in Nebraska gave final approval on Friday to adding a 30-day age limit to the state's "safe haven" law to protect unwanted newborns from being abandoned in potentially dangerous situations.

The absence of an age limit in the Nebraska law has sparked controversy over parental responsibility, as the majority of abandoned children in the state are teenagers.

As of Friday, 35 children have been abandoned under the law, including six 17-year-olds. Five have been from out of state.

Beginning in Texas in 1999, the so-called "Baby Moses laws" have been enacted in 47 states as an incentive for mothers in crisis to safely relinquish their babies to designated locations, according to the U.S. Department of Health and Human Services.

The newborns are protected and provided with medical care until a permanent home is found.

Safe haven laws generally allow the parent, or an agent of the parent who delivers the child, to remain anonymous and protected from prosecution, unless there is evidence of major negligence.