The trend of junior idols dates back to the mids, a period marked by significant increase in the number of child models and works involving individuals in that age range. Nikkei BP June : 48— Views Read Edit View history. From Wikipedia, the free encyclopedia. There exists no clear set of guidelines regarding the age at which an individual becomes a junior idol: Yumi Adachi , for instance, started her modeling career at age two and many other idols have starred in image DVDs at the ages of three, four and five. Concerning the contents of the titles put on sale, these include, in general terms, pictures or footage of the idols trying out a variety of outfits, such as school uniforms , bathing suits, gym clothes, yukata or even maid, police and anime-inspired costumes.