After spending more than 50 years thinking she was an only child, an Edmonton woman has been reunited with her long-lost brother.

Now, the two are joining together to search for a third sibling: an older sister neither of them has ever met.

Born in December 1960, Donna Harty grew up without siblings. But then Harty received an email last year from a man in Oregon, who said he was looking into his "family genealogy."

The man, Les Kahn, asked if Harty would be interested in helping him.

"I said sure, and he sent me another email," she said.

According to Harty, the second email read: "I think I'm your brother."

"That was news to me. I always thought I was an only child," Harty said.

She reached out to her aunt to verify the information, finally revealing a decades-old family secret.

"I phoned an aunt to say 'Is this possible? Did my mom have a baby?' And she said 'Yes Donna, she did.' "

Harty's aunt told her that Kahn was born out of wedlock in Edmonton in 1954. Her mother put the baby boy up for adoption, and asked her sisters to keep him a secret.

An American family adopted Kahn and raised him in California. Meanwhile, Harty grew up in Lloydminster, Sask.

Neither knew the other existed until Kahn decided to dig into his birth records.

They met in person for the first time this summer, at a gathering at Harty's home.

"I got out and we hugged and I said 'Long time, no see!' " Kahn said, laughing.

As the pair got to know each other this summer, Kahn revealed one more surprise.

During his search for information on his birth family, he said, he'd also discovered papers suggesting his mother had had a third child: a girl who was born in Edmonton in 1951.

Harty called her aunt and other relatives again to ask about this latest development.

"I went to my relatives and said 'Is it possible? Do I have a sister too? (And they said) 'Yes Donna, yes you do.' " Harty said. "I was shocked once more!"

Now, Harty and Kahn are working together to try and find their older sister.

They know she was born in Edmonton's Royal Alexandra Hospital in 1951, and that she was adopted by a family in Alberta.

Beyond that, however, the two have little to go on.

They've reached out to Alberta's provincial post-adoption registry, but under the law, the service can only release records if their sister has also requested contact.

"She may not even know she's adopted," Kahn said.

Still, he and Harty are hopeful that if they share their story, it may lead to another reunion.

"She needs to know that we want to find her," Harty said. "We're part of her family and she's wanted. We would like to find her. We'd like to know her."

With files from Newcap News reporter Jeremy Thompson