"Mum had some trauma as a teen," Green says from her home in Pt Chevalier, Auckland.
As a 16-year-old living in Bulls, with a father in the air force, Linda Green had a baby boy she was forced to give up.
"The fallout after that was quite full on and as a repercussion, she disappeared," Green says of her mother.
By her late teens, Linda Green was living in Perth. She met a man after a night at the ballet. His name was Clive, he was in his early 20s, had a South African accent but said he had Indian and Dutch parents.
The pair met in May 1975 and never saw each other again.
Green was born on February 15, 1976.
"She met him at Beethoven Bar after the ballet," Green says. "He was different to the types of men in her social group - with a Beatles haircut and a more conservative look. She thought he was passing through rather than a permanent resident of Perth."
Just before Christmas Green started the Facebook page: "Who am I? Can you help me find my Father. My name is Sarah Green".
"I'm quite realistic about the likelihood of finding him - my expectation is not high. There's a glimmer of hope, and there's that thought of how in this ridiculously huge world, these things are possible. The universe does actually seem quite small sometimes."
Green says her goal is to know who her father is, and where he's from.
"Maybe even to meet him," she says. "But that seems so far beyond.
"What seems maybe potentially viable is that he's got a cousin or a sister - someone that goes 'oh my God, this girl looks like she's part of our family, and my brother was in Perth at that time'."
But in the meantime, she's waiting. The Facebook page has been shared more than 4500 times, but she has yet to find any leads.
"I know that the older I'm getting, the older he's getting, and chances are probably diminishing. But it's constantly in the back of my mind.
"Every person has the right to know who their parents are and where they come from. There's a constant feeling for me that something's missing."
