Renee Liang reflects on having her and her family's stories fictionalised in her sister Roseanne's debut feature, My Wedding and Other Secrets.

From the age of 7, I knew the power of stories. My mother (to get a break, I realise now) packed us off for a nap every afternoon. We feigned sleep. Then, when the sound of her feet had faded safely from the corridor, I began. Rhea, one year younger, and Roseanne, the baby, snuggled up as I recounted alien adventures, rescues and random battles with light sabres - all starring us, of course. Roseanne, at age 2, was remarkably sentient, though I don't remember her saying much. She was a great listener, so long as I mentioned her in the story every now and then. The one disadvantage was that she liked to suck items of clothing as we slept, and more than once Rhea and I woke up to find our socks dripping wet.

We grew up of course, and through my teenage years I more or less ignored her as a short, somewhat intrusive being in my life. (She started talking a lot.) I think I was at university when I noticed her again. She'd started drawing. Fantastical aliens with pot bellies and blobby heads appeared on bits of paper. She also pinched out dragons from polymer clay, baking them in the oven when my mother was out. They were quite good. We asked her what she wanted to be. "A doctor," she replied.

"Why?"

"Cos everyone in the family is. I won't be able to understand you when you talk."

As a second choice, she admitted that she'd thought about being an animator. "Making stories. That might be cool," she said.

Time moved on. Roseanne worked her ass off in 7th form. She was dux. She learned she'd got into medical school. We harangued her through the summer months. Our friends, who didn't know her rang up and harangued her too. "You don't want to do medicine. Trust us, we're doing it."

No doubt she saw our persuasive wisdom, for she deferred her place and started a Bachelor of Arts and Science, graduating eventually with a Master of Creative and Performing Arts. The rest, as they say, is history.

Last week my sister, Roseanne Liang, released her first feature film, My Wedding and Other Secrets. It's a highly personal film - and quite a personal story for me too.

The original story goes something like this. Girl meets boy. Girl falls for boy and vice versa. Girl keeps relationship a secret from parents because she's worried how he might be received. Girl eventually breaks up with boy. Boy dies in a freakish accident of fate.

It doesn't sound like the synopsis you've read? No. That's because that's my story. And it's portrayed in the film as well, although not exactly the way it happened. More on that later. Anyway. Roseanne's real-life story had a far happier ending. If you don't know it already, watch the film. Because although it's a fiction, it's also very much a true story.

As adults, Roseanne and I have a tight relationship. We're close as sisters, but we're also close as fellow artists. She's a filmmaker, I'm a writer. We're both still figuring out things about stories. And we both draw on one of the most powerful type of stories - those about family - as material.

Although it's about love, My Wedding and Other Secrets is not the light romantic comedy that its marketing would have you believe. It's quirky, yes, and you'll laugh. But when I went to watch the screening, I snotted all over my face just like that infamous scene in the documentary the movie was based on, Banana in a Nutshell. Bring tissues, because this one might get you.

This is what I think the film is: a love letter to my parents. Because making a film is how my sister communicates. Making a film is how she tells them she loves them.

I'm crying as I write this, because learning to communicate with my parents has been one of the hardest things I've had to learn growing up - and I still feel as if I'm at a junior level. Not communicating with my parents meant that someone I loved died without being given the chance to be accepted by my family. And communicating is the task that hungrily, drivingly, bullishly at times, my sister set out to achieve.

I know there are some in the Chinese community who feel that telling such a personal story in public is wrong. When we were growing up my mum often taught us to put our heads down and keep quiet, even if something was unfair. There was a sense that, as newcomers and readily identifiable "outsiders", we should try to stay invisible. "Keep quiet and they'll let you get on with it" seemed to be the sentiment. It was not done to "hang your dirty laundry in public", no matter what the source of the dirt. And though sentiments have indeed changed as more of us find our strident Kiwi voices (after all, we were born here), my sister has endured walkouts, anonymous emails and insults so violent she had to talk to police. When these failed to provoke a reaction, the people she loved were taunted, or hurt in other ways. We have learned the downside of telling our stories. I hasten to add that there are many others who support us and go a long way to do so.

The thing is that any story, once told, becomes the truth and that is why people are so careful about the stories they tell. One could argue (forgive the writer's bias) that we are all made up of a collection of stories. In my sister's case, the need to tell her story, to have it understood, makes her both vulnerable and strong.

Communicating is important to her. You can see it in the film as her main character Emily tries and tries again to say how much she loves her mother. She stuffs up but she tries again (there's a strong gene for stubbornness in my family). Eventually, she learns to do, not say. It turns out that's how my parents have always told us they loved us. We were just too stubborn to listen.

I admit we all had our worries about the film. Aside from the community reaction, I worried about scraping open a wound that had only recently healed (by falling in love again). I want to say here that Roseanne has always been more than respectful whenever she's touched my story. Initially I was fiercely protective. I baulked when she and her co-writer Angeline wondered if they should merge mine and Rhea's stories into a single character. ("But I can't be married to Brad!" I protested.) But as a writer, I also knew the teaching that whatever you write must serve the story.

But is that really true? Who must the storyteller ultimately answer to? Herself? The subjects of the story? The community the story comes from? The audience she aims to connect with? These things are not clearcut, and there's no right answer. My sister decided that remaining true to herself was what this film demanded, and part of my tears on watching the film came because I saw that struggle. The documentary worked because it was so raw and honest. The film, although fictional, maintains that quality.

While the film was being shot, I spent time with my "pretend family" - board games, trips to the Lantern festival, "family" dinners. We all felt the absurdity of it. We felt close, and also quite strange. No one tells you this, but when a film deals with such recent history, the dividing line between fact and fiction doesn't stay still. Halfway through the filming my sister realised Michelle Ang (who plays Emily) was taking on her mannerisms, and she was taking on Michelle's. Little slips with names betrayed the cast and crew's confusion.

In making reality fiction, often the details are betrayed. I made exactly the opposite choice that my doppelganger, "Susan", makes in the film. I found the portrayal of my ex-partner two-dimensional - he was so much more complex than that. But then, my writer's brain forgives, even as my emotional brain worries that people might think it was the real story. My writer's brain argues that it's my sister's story and we are necessarily the side characters. Everyone tells history from a different point of view.

In the small moments I spent with my fake sisters - Michelle Ang, Celeste Wong and Kat Wong - I felt we could have grown up together. When we compared stories, some were quite similar. I think the power of any family story is its universality, and I'm hoping people will go the film, not because it's a Chinese story or even a Kiwi Chinese story, but because it's the story of a daughter wanting to express her love.

My sister has taken a family story - our family story - and unfurled our hearts to the world. In doing so, she has placed us at risk. But I'm proud of her. Proud that my sister is a filmmaker, and that she makes films worth watching.

*My Wedding and Other Secrets is at cinemas now. Dr Renee Liang is a paediatrician , published poet, playwright and short-story writer.