On April 18 episode of MBC FM4U's radio show 'The Date with Ji Suk-jin at 2PM' (literal translation), Yu Jae Seok joined the talk.

Yu Jae Seok answered, "Yes, I did. Years ago when my son was born, I honestly didn't think that I would cry, but I did. I thought I wouldn't cry this time, but I ended up crying again. I couldn't help it."
Yu Jae Seok explained why he cried, "I had this strange feeling that I just can't describe in words."

The host Ji Suk-jin said, "Yu Jae Seok is always at home on his day offs, looking after his newborn daughter Na-eun."
Yu Jae Seok commented, "That's something that I must do, you know. I feel like I'm only my wife's assistant though, since I'm out working most of the time. That's why I spend time at home on weekends and day offs."
With a smile, he added, "Na-eun is about six months old now. She started rolling over. My wife hurried me to see her rolling over three times in a row when I was getting ready today."

Their first child Ji-ho was born in May 2010, then Na-eun last October.
(Lee Narin, Credit= '2pdate' Instagram)
(SBS Star)