I'm currently watching 17 but 30 and getting slightly frustrated with either the translation or the script. At one point, a character mentions his nephew. Another person -- the housemaid -- refers to this nephew as a "niece." She even uses the pronoun "she." The first character never thinks that this is weird. Sure, everyone is weird, like really weird, but still... Why doesn't he care? Is it the translation or the Korean language, where nieces and nephews are just like younger sisters and brothers: genderless ?!
PS: I've written the post in this manner because I dislike spoilers. It's also fairly early into the drama.