Parenting commentator and educator Nathan Wallis with advice for parents worried that their kids are not making developmental milestones? When to be worried and seek help, and when to relax and let kids find their way.

They say it takes a village to raise a child. But parents shouldn't be overly anxious about their kids not making developmental "milestones", says parenting commentator and neuroscience educator Nathan Wallis.

In fact most of the milestones that parents worry about aren't really there, Wallis says.

"People get obsessed about walking whereas professionals aren't concerned about walking until about 15 months, if the baby isn't walking at 14 months that's fine."

When observing these so-called milestones, parents should take note of other indicators rather than evaluating it in isolation. Like in walking for example, they can look out for pre-movement indicators, seeing if the baby is pulling themselves up on furniture at 14 months or so.

"It's hard to give just one milestone and make it simply that every child is supposed to do this by this age, because the research always informs us about his imaginary average child so there's always ... a distribution of what's normal," Wallis says.

Kid will also often be born being better in a certain domain. For instance, often boys might develop motor skills before their language skills, Wallis says.

But again, this isn't a 'rule' of measure for all boys so parents shouldn't get too caught up in it.

"I can see why parents are concerned about . There's nothing else that quite marks your cognitive development quite as closely as language.

"But it's worth parents knowing that we divide language into expressive and receptive. Receptive language is the stuff you understand. We don't really measure a child's expressive language until after the age of two."

Wallis says that 90 percent of how much the kid speaks, the expressive language, will occur in a 10-month period between 26 months and 36 months.

"In that 10-month period, that's when you're really see that language bursting and that kid talking a lot with more complex sentences. Before that, we're measuring their receptive language ... it's just the way the brain works and the way you develop your language, you develop your receptive language before your expressive language."

Another factor that might get people worked up is whether the child is reading enough. But Wallis advises parents that it's more important to learn to love books than it is to learn to read books…

Go to this episode on rnz.co.nz for more details