What's it like to grow up as the child of a secret affair.

Rachael Johns never grew up questioning who her dad was or where she came from. She knew those facts well.

Her dad lived somewhere in England, half way across the world, and her parents met working together at a TV station. They were not married and they never had plans to. They weren’t engaged, and technically, they weren’t even dating.

They were, for lack of a better word, a ‘thing’ for about four or five years. And then she came along. The product of their secret affair.

“It was a relationship that happened over many years slowly and it was on-and-off for about four or five years before I came along,” Rachael tells Mamamia from her base in Perth.

“I can’t remember ever not knowing about where I came from. I grew up without a father figure obviously, and you notice that on Fathers’ Day and at some school events, but I had a grand dad. Honestly, it was one of those things where you don’t miss what you don’t have.”

It was 1979 when Rachael's mum realised she was pregnant and, far from seeing a future where her partner was ever going to be in the picture, she packed their bags and moved them from England to Australia.

Though she can't remember a point in time when she was explicitly told about her origins, Rachael says she never grew up wondering. Things were OK. She felt loved and well-adjusted, and felt the occasional pangs of curiousity about her father and the four half-sisters and brother who never knew she existed.

"It's not like my mum ever condoned affairs, she knew that was wrong, but she was never ashamed of me.

"Theirs was a love affair, he was unhappily married and 13 years older. She never asked him to leave. I was my dad's dirty secret, and that caused a lot of issues down the track. His wife suspected but never knew."

For 17 years, Rachael's siblings had no idea she existed. That was, of course, until she decided to chase her father and her family down.

"We didn't have the internet back then. It was just so lucky that I found him. We went down to the state library, looked at the phone book and he hadn't moved or anything so he was pretty easy to track him down. By that time, my mum's loyalties lay with me, so she was worried it could end up not very nice and I could end up upset."

When she found his address, she picked up a pen and wrote him a letter. She was coming to England, she said, and she wanted to meet her whole family.

"I actually think talking to him about it later, it was a kind of a release. He was very apologetic he hadn't come clean."

Largely, she said, her sudden appearance into their lives was well-received. A couple of her half-sisters were hesitant to meet her out of a sense of loyalty to their mum. But the others were welcoming.

"It made me realise that secrecy never works - in the end it always comes out. In fact, the longer someone doesn't know someone the harder it will hurt them."

It was watching different people react to her situation that helped inform key parts and themes of the novel she decided to then pen. Rachael, a best-selling author, has written her latest novel, The Greatest Gift, about the beautiful complexities behind the relationships forged through egg donation.

Being the child of a secret affair, she says, has taught her a child should always know where they come from. Without that knowledge, you run the risk of raising a child with quite a complex.

Most Australian states now have legislation making sure all donors consent to their identifying information being held on a registry. These children can always find out where they came from.

For Rachael, this was crucial for her growing up to have a clear picture of her identity. And so, in some ways, her childhood was not so different to those kids who grew up as the product of egg donation.

"It's interesting, I actually started writing just before I met my dad. I never thought about the connection there, but I do think writing was a form of therapy for me then.

"[When you write a novel], you do draw from your own experience, but there is always a new element that comes into the story. I was just fascinated [by the concept of egg donation]. Writing this book opened up a whole new community for me."

The Greatest Gift RRP $32.99, published by HQ Fiction, is available here, and at all good book stores.

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