In today's globalised economy where companies relocate employees to different parts of the world for business reasons, the generation of third-culture kids keeps growing.

Unlike many third culture youngsters who have problems adjusting to living in different cultures and wondering where they belong, Wiersch has a strong sense of her roots and family, one of the founding families in her hometown. She can speak fluent Hebrew, her mother tongue, and she visits her hometown in Israel regularly.

"I spend every summer there working in a cafe, which gives me the opportunity to integrate with the local community," she says.

Wiersch already plans to join a two-year military service next year when she finishes secondary school in Hong Kong.

"Everyone in my family has served in the army and I don't see why, simply because I happen to live in a different country, I can ignore my duty. But whether I will stay and live there, I don't know," she says.

"To this day, I don't really feel like Hong Kong is 100 per cent [home] but neither is Israel. They both seem like a bit of a pit stop towards the future. This is the main disadvantage with being a third-culture kid - you don't really have a country you consider home," Wiersch says.

The story of Haruka Nuga, however, is quite different. Born in Yamagata, Japan, the 22-year-old University of Hong Kong graduate moved to the city with her family when she was just a few months old.

"In Hong Kong, I'd be considered Japanese but in Japan, I'd be called - it's a term used to refer to Japanese children educated and brought up overseas," Nuga says.

"When I was younger, there were many moments when I would feel ambivalent about my [lack of] identity. I feel like I don't belong to any one culture. I grew up going to American schools where I was exposed to the Western culture. Many people would consider me 'whitewashed'," she says.

Her confusion towards her identity is justified and could be shared by many third-culture children, says Dr Paul Pang Hok-hoi, a registered psychologist working at Bliss Hong Kong Holistic Centre.

"The formation of our identity is a continuous process throughout our lives; it begins in childhood and becomes particularly important during adolescence," he says.

If not handled properly, Pang says such confusion could lead to an identity crisis which could result in aggression and depression.

Luckily, Nuga hasn't experienced such extreme consequences. Nevertheless, she has lived with some unhappy memories, like a high school assignment she still vividly remembers.

"Our history teacher asked us to go home and ask our parents and grandparents how they would feel if we married a Japanese person. And I thought how odd."

During the next class, when her Hong Kong friends all shared similar answers saying their grandparents would never allow that and how some would burst into tears when asked, she felt very uncomfortable.

"I kept trying to defend myself by thinking: but I'm not really Japanese," Nuga says.

"I barely speak the language or understand the culture. It was then that I realised no matter how different [my upbringing] may be, I am still ethnically Japanese."

Nuga has never shared her feelings with her parents.

"It's hard to communicate with them or discuss anything slightly complicated because I can't express myself fully in Japanese and they don't speak English.

"I feel a huge generation gap between me and my parents also because I have a more Western approach and view of many things - the books I read, the music I listen to, the TV shows and movies I watch are all from Western culture."

Nuga's mother knows her children are not growing up as traditional Japanese, but she has accepted it.

"Haruka is Japanese but she is not Japanese. I see her as a 'foreigner' because she speaks English and has never attended Japanese schools," says the 49-year-old woman who has lived in Hong Kong for 23 years.

"But since we're in Hong Kong, I think it is best that she and her sister go to international schools and speak English. English is a language that can be used around the world and it opens a lot of doors for them.

"The [downside] is they don't understand (the formal way of addressing people, such as the elderly, in a respectful way) and our Japanese mannerisms," she says.

Raising a third-culture child is also a challenge for the mother who says: "The most difficult part is [seeing] how they live so independently, doing what they want and not considering other people. It is different from Japanese children who are more inclusive of others, who will say or do things that suit everyone rather than voicing their own feelings."

Wanting to learn more about her culture, Nuga began to take Japanese lessons last year. Two years ago, she also signed up for a project in her journalism course to visit Tohoku region in Japan for the anniversary of the devastating 2011 earthquake.

The trip has had a profound impact on her identity search.

"It hit me that I didn't fit in as I didn't know how to communicate and I was like a foreigner. But standing in the area where people used to live and go to school and seeing the mounds of debris and empty broken houses was surreal," she says. "After the trip, I wanted to try to go back to Japan and learn more about myself and about my home country."

She has also come to terms with her sense of identity.

"I don't think there's anything wrong with not being able to identify with one's [original] culture, ethnicity or country. Living in Hong Kong has made me a global person. Hong Kong is my home. I'm most comfortable being here. But I have never lived in Japan so who knows, I might grow to consider it home, too, if I had the chance," says Nuga.

That's a sensible approach, says Dr Pang. "Having a global identity is inevitable in our growing trend of people living in multicultural and diversified societies. It's a tool for us to communicate with others in reality, which will benefit our [development of] identity in the long run," Pang says.