Only children by definition are human beings who have no siblings. They grew up with just their parents, which means they got all the toys and attention they could ever need or desire. They never had to share or fight with another being. They never had to get in trouble for hitting their brother or sister or fighting over who gets the top bunk. Sounds like a good life. Here are the female K-Pop stars who are only children:

f(x)'s Victoria

Girl's Day's Yura

miss A's Min

Kara's Nicole and Gyuri

Wonder Girls' Yoobin and Sunye

After School's Lizzy and Nana

T-Ara's Eunjung