His son was born with a rare condition, so this father donated a kidney. He "always knew it was going to be him."

When Stephen Munari's son Jaren was born, Munari knew he would one day donate an organ to help him. 

The day before his birth, doctors told Jaren's parents that their son would have just the one kidney, which was "on the small side," his mother, Donna Griebel, told CBS News. 

Jaren, now 9, was born with a rare congenital disorder called branchio-oto-renal syndrome. Just one in 40,000 people are diagnosed with the condition, according to an estimate from the National Organization for Rare Disorders, affects the kidneys, the ears and the neck.