Aboriginal children who were raised by non-aboriginal adoptive families face challenges as adults in finding their cultural identity, says a Manitoba First Nation leader.

Grand Chief David Harper of Manitoba Keewatinowi Okimakanak (MKO), which represents northern chiefs in the province, says he has heard stories of aboriginal children being placed with non-aboriginal families during a period called the "'60s scoop."

"They picked up these children years ago and we don't even know where they are," he said Tuesday.

"Half of them, most of them came back, but there's still children out there that do not know who their true mother is."

Harper said he cannot comment on the specifics of a legal case involving a Winnipeg couple and an agency under the Métis Child and Family Services Authority over the long-term placement of a 2½-year-old boy, but he spoke generally on the issue of aboriginal children in care.

The foster parents told CBC News they were told they cannot adopt the boy, who they have had in their care for nearly two years, because they are Filipino and child-welfare officials believe the part-Métis child should be placed with a more "culturally appropriate" Métis adoptive family.

The child's permanent guardian is an agency under the Métis Child and Family Services Authority.

The foster parents, as well as the child's biological mother, have argued that a bond has developed between the couple and the toddler, and that should be a bigger factor than one part of his cultural background.

But the Métis Child and Family Services Authority has said if the primary caregiver identifies as Métis, its mandate is to place the child in a Métis home long-term.

Authority CEO Billie Schibler told CBC News that officials want to do what they believe is in the children's best interests, as well as preserve Métis culture and families.

Schibler also noted that from the 1960s to the early 1980s, thousands of aboriginal children were placed with non-aboriginal families as part of the '60s scoop.

While Harper defends the right of a child and family services authority to place children where it believes is best, he said communities also need to devote more resources into keeping children out of the foster care system in the first place.

"Where there's no running water, where there's overcrowding, of course government will say, 'No … that's not an appropriate home for a child to be raised at.' But in the meantime, we're shipping children to urban centres," he said.

When children do end up in care, Harper said it's important that foster families help children stay connected to their cultures.

The General Manitoba CFS Authority says it offers classes to help families connect foster children with their cultures, and staff do place children in culturally appropriate homes when available.