Robinson and Macfarlane, of Oahu, told their story this week to local television stations in Honolulu after hosting a party on Saturday to tell their families.
Recreational DNA tests have grown in popularity in recent years as the price of testing kits offered by services such as 23andMe, Ancestry.com and Family Tree DNA, have dropped to around $100 or less, despite some lingering privacy concerns. The results can turn up information about distant or unknown relatives.
The men met as adolescents decades ago and went on to play football together at the Punahou School, a private high school on the island that counts former president Barack Obama among its alumni.
“When we played for Punahou, we were both first string,” Macfarlane said in a video posted by KITV 4. “We’re brothers, playing side by side.”
Even though the two had similar interests and looked alike, according to some people who knew them, they said they never considered the possibility that they are related, the station reported.
“It never crossed my mind,” Robinson said. “That’s what’s really amazing.”
Robinson was adopted by his family while Macfarlane never knew his father, another local television station in Hawaii, KHON 2 reported.
“This guy was like an older brother all along,” Robinson said. “We’d go skin diving; I’d be making noise in the water, splashing around, he’d be teaching me how to do it right. He always came out of the water with a bigger string of fish. And I had the smallest.”
“As it should be,” Macfarlane chimed in. “You’re my younger brother.”
Macfarlane took a DNA test after trying to seek information about his family online.
“So then we started digging into all the matches he started getting,” Cindy Macfarlane-Flores, his daughter, told KHON 2.
A username Robi737 came back atop the list of DNA matches. “Robi” was one of Robinson’s nicknames; he used to fly 737 airplanes for Aloha Airlines, Macfarlane’s daughter said. Robinson had also taken a DNA test, the results of which had been uploaded to Ancestry.com.
Marfarlane and Robinson had identical X chromosomes; the men did research and learned they had the same biological mother, KHON 2 reported.
DNA tests can sometimes lead to uncomfortable surprises
; finding out that a parent or close relative is not actually related, for example. 23andMe no longer provides data on these types of results, but in 2014, estimated that 7,000 users of its service had discovered unexpected paternity results or learned about previously unknown siblings.
Robinson and Macfarlane described their surprise finding in positive terms.
“Yeah it was shock,” Robinson said. “It was an overwhelming experience, it’s still overwhelming. I don’t know how long it’s going to take for me to get over this feeling.”
The two, both retired, plan to do some traveling together, KHON 2 reported.
“This is the best Christmas present I could ever imagine having,” Robinson said.