do kids of permenant residant parents need a white passport to travel out of the USA for more than a year ?

a white passport is a reentry permit.

White passport?

Assuming the kids of the permanent resident parents are themselves permanent residents and not US citizens born in the US, then, yes. If they know they intend to remain out of the US for more than a year, but less than 2, they would need to apply for a re-entry permit, and receive it, before departure. Any permanent residents who remain outside of the US for more than a year without a re-entry permit would lose their green cards. If they were born here then they'd use US passports, like any other citizen.