Tonight the ABC's Australian Story tells the tale of an improbable romance between a sperm donor and receipient.

IT was the story we told you last week about an improbable modern family - a back-to-front love affair in which a woman seeks out and falls in love with an anonymous sperm donor who fathered her baby daughter.

Aminah Hart and Scott Andersen’s unconventional love affair became a global headline after a story about their union aired on Australian Story last Monday. Now ABC News reports the couple has become engaged and will marry at the end of next year.

They were on holiday in Thailand when the Australian Story episode aired and were inundated by global media for interviews about their unusual meet cute.

Advertising professional, Aminah, met Scott, a farmer, just before their daughter Leila’s first birthday.

Aminah had lost two baby boys to a genetic disorder passed on from mother to son. At 42 and newly single, she felt anonymous sperm donation and IVF was her last chance to mother a healthy child.

“It takes the romance out of it a bit, doesn’t it, when you decide to take on donor sperm to try and have a baby,” Aminah said.

Three bits of paper that outlined the features of each potential donor were all she had to go on.

Of the five donors, one stood out. He described himself as happy and healthy, tipping the scales in his favour for Aminah who hadn’t had much of either in recent times.

Scott Anderson, a twice-divorced father of four himself, spends his days artificially inseminating cattle, so helping someone else make a family didn’t seem such a stretch. But he told no one about it, never expecting anyone to come looking for him until he was elderly.

“A lot of people think, you know ‘He’s a shocker, that bloke you know?’ And I got a little bit of that so it’s kinda good to tell the real story so people know. Cos you couldn’t make that up,” Scott said.

When Aminah’s blonde haired, blue eyed baby, Leila, was born two years ago, Aminah — who had never known her own West Indian father— became curious about the anonymous man who had helped make her.

Once Aminah’s mother declared she was sure she had found Leila’s biological father by googling clues to his identity, Aminah made a formal request for contact. And the rest is history with the pair now together, a year into a happy relationship.

Scott had been in a relationship with another woman when Leila and Aminah came into his life, but the woman believed he shouldn’t be spending so much time with the baby he helped conceive, so they broke up. Not long afterwards, Aminah and Scott began a romantic relationship.

“It’s real Mills and Boon stuff isn’t it? It’s a bit of a fairy story really. But it’s real so that’s good. It’s not just a dream you know,” said Helen Marshall, Aminah’s mother.

“I thought this must be the first time this has ever happened in the world. What are the chances of that happening?,” said Julie Buxton a friend.

Watch How I Met Your Father on Australian Story at 8:00pm Monday November 3.