When strangers ask Craig Heatley how many children he has, he has to pause before deciding how to answer.
"We have three children with us. The eldest, Addison, is a surviving twin and she's eight. Ella is five and Owen is three," is how he normally responds.
But Craig and his wife Lara also had two other children. Their first child, Charlotte, was stillborn at 35 weeks gestation in 2007. Addison's twin Cameron died in 2009 from a suspected febrile convulsion in his sleep, aged 22 months.
"I try not to look at photos of Cam [the couple don't have any pictures of Charlotte] now in public, because someone will see you and say 'That's a great picture of your child, how old is he?' and you have to explain," Craig, 43, from Perth, told news.com.au.
"But sometimes you've almost got to challenge yourself and look at photos and videos to remind yourself what actually happened.
Around six months ago, my wife said she was started to forget what [Cameron] sounded like. Sometimes you just have to do it," he said.
Craig is sharing his story as part of International Baby Loss Week and to support SIDS and Kids, a charity which funds research and awareness campaigns about deaths of babies and children.
The day after Craig and Lara found out Charlotte was stillborn, at a scheduled doctor's visit, Lara was induced.
"They told us that her heart had stopped beating and they had to get in and do what they needed to do," Craig said.
"We held her for a little while, probably for about a day, before we saw her off. It wasn't a lot of time, but it was enough time to say our hellos and goodbyes," he said.
Less than two years later, Lara found Cameron lying still in his cot at 5am. A febrile convulsion is a fit or seizure caused by a fever, where a child's body temperature increases too quickly and the body shuts down.
"She couldn't rouse him, pick up him or pull him out. She said he was unresponsive and we called an ambulance and police around to help, but it was too late," Craig said.
Addison, Ella and Owen talk openly about the siblings they've lost.
"We have photos of Cam around ... we don't try to hide it," Craig said. "Addison knows she was a twin. She knows he existed and she spent time with him.
"At Cam's funeral we had a big photo of him up and she was tapping it and looking around for him. Then she started to cry. She openly talks about it and asks questions.
"That's the part that can be a bit tough. She asks these innocent questions like 'Where's Cammy, where's Charlotte?' She's very aware. She's fantastic but she can catch you off-guard occasionally," he said.
It's the little things - like hearing a train roar past - that remind Craig of his son.
"He loved Thomas the Tank Engine and when we'd drive down the freeway and see the trains, every time he would make the 'choo choo' noise.
"Now when I'm driving to work and the train goes past, I think of him. It does get to you," he said.
"It's terrible when I go to things like sports carnivals, because there should be other kids running around. You find with time, instead of it getting easier it's gotten harder. I think because you start to realise what you've missed and what could have been, the loss of the potential."
It's not an easy topic to talk about, but Craig says there is a direct correlation between media coverage and awareness campaigns about child deaths and a reduction in SIDS cases.
"If we can help contribute to further to research and awareness in Australia so that parents can make informed decisions, that's the best thing we can do to help reduce deaths," he said.