The way we look at the "picket fence" family life that underpins New Zealand's social policies does not match the reality of many young people's lives, new research shows.
Only a quarter of teenagers in an internationally respected study were living with their biological parents at age 15.
The University of Otago research is based on life histories of 209 15-year-olds taken between 2007 and 2012 who are children of members of the Dunedin Study.
The research found many young people had complex and dynamic whanau/family arrangements. The researchers found that most of the teenagers had experienced multiple changes in household composition, and just 26 per cent were living with both their biological parents at 15.
Participants experienced up to eight changes in care arrangements by that age. Fewer than 7 per cent had lived their whole lives in households made up of only their mother, father and siblings.
More than half the children, 63 per cent, had been cared for by two parents at birth. But by age 15, 59 per cent were either in sole parent or some form of multiple-resident care, including shared arrangements between parents in different households.
Next Generation Study manager Judith Sligo believed that support for young people and their families would be improved if there was more awareness that "there's a big diversity in family arrangements". It was sometimes assumed that only "certain types of people" had these "dynamic family arrangements", but they were much more widespread, she said.
The level of complexity and change in family life shown by this research contrasted with the "simpler and more static view of household and care arrangements" that underpinned policy-making involving young people.
The Working for Families programme required the principal child carer to notify Work and Income New Zealand whenever they had a change in circumstances, she says.
The Otago findings suggested this was was "unrealistic and likely to cause many children to be excluded from this policy". New Zealand's social policies should be developed and delivered with the child at the centre, acknowledging cultural context and the dynamic nature of young people's living and care arrangements, she said.
The research findings have been published in Kotuitui: New Zealand Journal of Social Sciences.
What does family mean?
Blended family - Sarah Harris, 25, Auckland
My family is confusing but great. My mum's been married twice, my dad thrice. In that mix I've got three older half-siblings, three older step-siblings and one little brother.
People usually paint divorce as failure, but 12 years after my parents separated I'm its biggest advocate.
Mum was 19 when she met dad who was 30 and already had three kids. Mum is quiet and artistic, dad is loud and dominating. They were married for 25 years. But by splitting up they found partners who are more like themselves and I've never seen them happier.
It's also opened up two new families for me to be a part of.
I really value getting among my step parents' families and joining in with their traditions and celebrations. I've often heard people saying they're staying together "for the kids" but my advice is - don't! Your children are better off to see what a successful relationship looks like, rather than a loveless one.
Nuclear family - Jessica Parulian, 25, Auckland
When you have a nuclear family your parents' lives are completely interwoven, says Jessica Parulian.
The 25-year-old's mum and dad met in high school when they were 17 and 16. Now, 38 years later, they have three daughters, share a business and are still very much in love, she said.
"It's always been very constant and very steady ... I hardly ever see them fight. They share all their responsibilities and their friends."
Parulian said her extended family shared the traditional structure. Their Christianity, Chinese culture and the fact they had all grown up together probably had something to do with it she said.
"In Christianity they don't enter into marriage as lightly. It's a sacred relationship."
Parulian loved being part of a family that was devoid of awkward dynamics. You never had to choose who you spent time with or worry about who comes on a family holiday, she said. "I just find it really comforting. It's nice having everyone around all the time. You just invite everyone to everything and you know it's not going to be weird."