Yoona was born on May 30, 1990 in Seoul, South Korea. Her family consists of her father and an older sister by five years.While growing up, she listened to girl group S.E.S and dreamed of becoming a singer. In 2002, she was cast in the SM Saturday Open Casting Audition and spent five years "doing nothing but constant training" in singing, dancing and acting. During her trainee days, she had low self-esteem about her low voice, and once thought of giving up singing in order to pursue an acting career. A SM choreographer persuaded her to continue, saying it would be "a waste to give up becoming a singer" with her "outstanding dancing skills". He also considered her as the best female dancer within the agency. Vocally, though Yoona is not known to have a wide vocal range, she has been described by critics to have a "very sweet voice". Prior to debuting, Yoona was introduced to the public through various appearances in music videos and commercials; she first appeared in TVXQ's "Magic Castle" music video in 2005.She made her official debut as a member of Girls' Generation in August 2007, becoming the "center" of the group.The group gained significant popularity with the release of their hit single "Gee" in 2009.