Stay-at-home fathers were once a rarity, but now many are the primary caregivers

It's a weekday morning and Chung Sang-hoon, 34, is at home with his two small children, classical music playing in the background.

Fathers like Chung, who has taken a year of paternity leave from his job in sales with a big foreign company, were once so rare in male-dominated South Korea that they are called "superdads". But their ranks are growing.