"There's no words that can describe how thankful we are to you Michael, you saved our son's life," Aileen Cooper said on the video call.

"It's my honor," Speck told her.

Speck had donated part of his liver to 10-month-old Jacob Cooper. Jacob was born with biliary atresia, a rare disease of the liver and bile ducts that can be deadly.

"Your son is born with an issue, and then somebody from across the country you have never met shows up to save his life," dad Chad Cooper said.