To stay healthy, experts say children and young people need to do at least an hour of physical activity - such as walking or cycling to school and running in the playground - every day.

Dental health should be a higher priority for Hong Kong families, according to two studies by the University of Hong Kong's dentistry faculty.

One study found around half of preschool children, aged four to six, showed signs of tooth decay. An average of two teeth were affected by decay in every child. Decay was less common if children snacked only once a day or had started brushing their teeth by one year of age.

In the second study, almost all of the 324 18-year-olds examined had unhealthy gums. About two-thirds said they brushed their teeth at least twice a day, but only one-fifth used dental floss and about half had seen a dentist in the past three years.

Most countries regard corporal punishment as child abuse. Here, smacking is a form of discipline still considered acceptable in most homes. There are countless studies that support a ban. Research published in November by the University of New Hampshire Family Research Laboratory found university students who were spanked as children were more likely to engage in criminal behaviour. Students that were spanked by both parents were also more likely to be involved with crime.

"The results show that spanking is associated with an increase in subsequent misbehaviour, which is the opposite of what almost everyone believes. These results are consistent with a large number of high quality peer-reviewed studies," says the lab's joint director Murray Straus.

The research covered 15 countries and territories, including Hong Kong.

There really can be too much of a good thing, according to research by City University. It claims parents who overindulge their children are in danger of producing a generation of aggressive and overconfident young people.

Annis Fung Lai-chu, an associate professor in the department of applied social studies, gave 9,400 pupils with an average age of 11 a questionnaire that detects antisocial traits, narcissism, and measures their views of the outside world.

The average level of narcissism displayed by youngsters was 3.89 on a 14-point scale - higher than the 2.9 for children in the United States, 2.81 in Australia and 2.36 in Britain.

About 16 per cent showed signs they were aggressors or tended to bully. Fung says this worryingly high level puts them more at risk of developing disorders that could turn them into violent offenders.

"Parents are giving too many things to their kids, making them feel good about themselves. Such 'monster parents' overprotect and make children narcissistic. This can be potentially dangerous," she says.

Play is one of the rights of the child, according the United Nations Convention on the Rights of the Child. It is also widely recognised as having tremendous benefits on the social, mental and physical development of a child.

However, according to Irene Chan Man-tuen, chief executive of the Hong Kong Committee for Unicef, it is often one of the forgotten rights. As a result, children today have 1.7 hours less of daily play than a child born in the 1970s.

Unicef believes all children should have at least one hour of unstructured play every day.

"We are not talking about computer or video games, television or any activity in a tuition environment," says Chan.

"It should be physical, outdoor, unstructured play which is totally initiated by the child."

A survey by Capital Medical University in Beijing, published in September, highlighted one other benefit from playing outdoors. It found that children who spend less time outdoors and more time inside were more likely to develop myopia - or short-sightedness.

Achieving a work-life balance is something families here have always struggled to get right. Part of the blame has been given to employers who have failed to create family-friendly workplaces.

A poll by the Federation of Trade Unions found that of 953 fathers surveyed, 78 per cent said they spent less than an hour a day with their families.

A poll in August by the University of Hong Kong asked 1,048 full-time workers to rate their work-life balance on a scale of one to 10, where 10 was considered ideal.

The average score was 6.1, which has been virtually unchanged for the previous eight years.

The survey, commissioned by Community Business, a non-profit organisation that promotes corporate social responsibility, found 35 per cent of people polled said they had considered quitting or had resigned so they could spend more time with their families.

Community Business senior programme manager Amanda Yik says bosses should be more flexible about working hours so parents can spend more time with family.

Late nights and lack of sleep are common but the consequences can be far-reaching and not only affect concentration but also long-term health and well-being of children, say experts.

Lack of sleep is linked to an increased risk of obesity. In a recent study by Chinese University, it was linked to spikes of high blood pressure among school children aged 10 to 18.

Another ongoing study by Chinese University spanning the past decade has found sleep deprivation is a common problem among Hong Kong students. It is also getting worse with schoolchildren sleeping far less than the 10 to 12 hours a night recommended for primary school students and 10 hours for adolescents.

The study concluded that parents could encourage better sleep by establishing a bedtime routine that helps children wind down before bed. This includes keeping them away from the television and limiting access to social media and text messaging at night.

There is a growing body of evidence suggesting it is not-so-smart for both parents and children to spend long hours on smartphones and handheld devices. A three-year study by the department of rehabilitation sciences of Polytechnic University and the Hong Kong Physiotherapy Association found that excessive use of these devices could increase aches and pains felt by children and their parents.

Of the 1,049 people surveyed in September's study, 70 per cent of adults and 30 per cent of children and adolescents reported musculoskeletal pain from using electronic devices.

The researchers warned of posture problems such as rounded shoulders, a "poking chin" posture and degeneration of the thumb as a result of leaning over devices and texting, which would be difficult to correct in adult life.