What age should kids wear clothes in public or at home?

My 3-year-old blissfully walked along a beach in her birthday suit a few nights ago.

At the moment, this is her preferred state of dress and I encourage it (there are only a few years you can strut around like this without being arrested, so make the most of it I say).

I thought it was cute, other people thought it was cute, but was it appropriate? And is it smart parenting?

The answer is: it depends, it depends, it depends.

There's no hard and fast rule for what age kids should robe up in public or at home. That decision will come down to a mix of your child's development, your culture, the expectations of society and your thoughts as a parent on protecting your child and their privacy.

It's a complex issue, according to associate professor Kirsty Ross, a clinical psychologist who specialises in child development at Massey University.

"There are some families that are super comfortable with their children being nude and I don't want to tell them that they're doing the wrong thing because there is an element of personal preference on this as well.

"But it is also you are the person making a decision for your child - that's something that you really [need to be] thinking through."

When do kids start realising they're naked (and everyone else isn't)?

Young children lack what psychologists call "theory of mind", explained Ross

"Their world is very much through their own eyes.

"They are not able to observe themselves and see themselves as other people see them... the fact that they're naked, it almost stops being visible to them because they're not able to observe themselves."

Kids start to really develop theory of mind at around three or four, said Ross. Children will also be absorbing social and cultural cues, along with the boundaries you model as a parent.

Parenting coach Justine Lamond referred to that toddler/young child age as a person's "ecocentric stage of their development, which means it is pretty much all about them".

She also noted that boys' and girls' development speeds are drastically different at this stage, with girls about 18 months ahead.

"Girls are cognitively way further down the track compared to our dear boys, which means we might have to give our boys a bit more grace."

So when might a kid in New Zealand start covering up in public? After a lot of umming and ahhing, Ross landed on about five. Anything older might seem out of the norm for a kid in New Zealand to be running around starkers at the pool or beach, she said.

Council pools in Auckland and Wellington require children under three to be in swim nappies and those over three to wear appropriate swimwear while in the pool area.

What age kids will be roaming nude and free around your home will hinge even more on family philosophy.

Ultimately, many kids will naturally start to shy away from public nudity or being naked at home as they start "internalising some of those messages around privacy," said Lamond.

How to get your kid to put clothes on

It's not uncommon for toddlers and young children to go through a short or long phase of not wanting to put clothes on for preschool, outings or at home. There are many possible reasons for this.

It could have to do with their sensory profile, said Lamond.

"For many parents, what they encounter is that they have a child who feels things strongly and that certain types of clothing [are uncomfortable], they may end up having to cut labels out."

Kids don't get a lot of autonomy, but one area they do have power is over their own bodies, said Ross.

"They get told what to eat and what to do and what time to go to bed and all the rest of it so a feeling of 'No, I'm not going to wear that,' is a sense of autonomy and independence."

Allowing your child to pick what they will wear - giving them some power in the situation - is another strategy.

"There's some degree of control that you give, but there's also a bottom line where this is actually happening," said Ross.

When a child does want to be naked at home or in public, it's a teaching moment to talk about our public and private lives, and the difference between the two.

"It's about 'Your body is for you. It's precious and it's private and so we put clothes on to make sure that this is the way it's maintained', so they have a sense of ownership over their bodies," said Ross.

Parents need to ensure they don't approach the concept of privacy with a side of shame. It's something that could be challenging for mums and dads because this was unlikely a conversation that was modelled well by the previous generation, said Lamond.

"In a way, you're not just raising your kids, but you're raising yourself to be able to have conversations about sensitive topics."

Having open conversations not based on shame throughout childhood will encourage kids to continue to approach their parents for advice or help when they are teenagers.

What are the risks of public and private nudity for children?

There is a risk that someone could take images of your naked child in public and sexualise that image for personal gratification, said Barry Kirker, an Auckland-based clinical psychologist who works with sex offenders.

He's had clients who have been caught with images of children they've taken in public along with child porn from online. Or they've gotten excited by seeing a naked child in public and started searching out child porn.

"It's very unusual if they would act on it in public because there are lots of people around and they would realise they wouldn't be able to get away with that," said Kirker, advising parents not to be too concerned in public.

"It's not that many people that have that true interest [in children] and the odds of them being at that particular beach when your child is naked, it would be pretty low."

He said it would be realistic to believe that about one percent of New Zealand men met the definition of a pedophile, meaning someone who is sexually attracted to prepubescent children. About one in 20 men have committed a sexual offence against a child, Kirker estimates. (Women can offend too, but incidents are rare.)

A large majority - about 90 percent - of children who have been sexually abused were abused by a family member or family friend. This makes Kirker much more concerned about nudity inside the home than outside.

He's had cases where relatives without any prior history found themselves aroused by a child. Some of them acted on that desire. Others did not and sought help from someone like Kirker.

"I know there are some families that all like to get naked together at home, but that is what I would call a risky situation."