"He's nothing but a gift," Farrell, 31, said about son James on the Irish interview show Tubridy Tonight. With paternal pride he said: "As far as I'm concerned he's exactly the way he should be."
Though he was on TV to promote his latest movie, In Bruges, Farrell addressed the topic of James, whose Angelman Syndrome was revealed publicly last year.
"Angelman's is a neuro-genetic disorder," he explained. "The 15th chromosome is dormant. It affects their fine motor skills. They say that one in 30,000 children is affected by it."
According to his father, before James had celebrated his first birthday, he was showing signs of illness, which led to an early diagnosis for the boy.
Early Intervention"I've been very lucky that it was early because he started having seizures at about eight or nine months," said Farrell. Initially doctors thought James had cerebral palsy but soon he was diagnosed correctly and "we got early intervention," said the Irish actor.
The genetic disorder, which can impair speech, movement and balance meant that James walked his first few steps last fall, when he was 4. "It's just different," said the actor. "It's not different to me. He has his own path. He's just brilliant."
Farrell shares custody of his son with the boy's mother, model Kim Bordenave. He said he decided to go public about his son's health after people started asking questions about his involvement with the Special Olympics.
"I didn't talk about my son [but] I felt like I was betraying him, like it could be misconstrued as shame, which would be terrible, because he's such a celebration," says Farrell.
Questioning the concept of "normal," Farrell says his son is happier than so many people in the world. "I look around and I see people who move perfectly, who walk with grace, who speak with great diction and clarity and a great use of the English language and we're all miserable f---ers – including me, at times.
"And then I see this fella who doesn't move the way what's perceived to be 'normal' is, and he's as happy as can be."