What is anime without the over-sexualization of women's breasts?
Big breasts have become extremely popular in modern society amongst many men, to the point where some women pay for breast enhancement surgery--commonly known as a "Boob Job"--to increase their bust size to either appear more attractive or feel more confident in general. Some men however, prefer small boobs.
The concept of big boobs in anime and manga goes as far back as the 1980s as anime began to gain popularity worldwide. Series such as Kotetsu Jeeg Robot and Shoten Doji presented female characters with sometimes oversized breasts. Though the shows with big breasted girls were few and far between in that decade, the concept started gaining popularity during the 90s, when mainstream shows such as Ghost Sweeper Mikami, Neon Genesis Evangelion and Ghost in the Shell featured big breasted women as major characters.
Story-wise, big breasts are often used as a source of jealousy (see the breast envy page) between female characters in series such as Kodomo no Jikan or Girl’s High. Some shows do the opposite, like in Lucky Star, where Konata (a flat chested girl) often makes fun of Miyuki for having big boobs. Some anime and manga incorporate big breasts into the plot much more prominently. In Manyuu Hikenchou, female characters with very large breasts are worshipped by society, while women with flat chests are barely considered human.
Big boobs is one of the most popular genres in hentai and even becomes major part of the story in movies like Milk Money, Milk Junkies and Mother Knows Breast. The first popular big boobs hentai was Cream Lemon, other big boobs hentai include: Pachira Teacher, Viper GTS, Taboo Charming Mother, The Bible Black Series, Stepsister, Shion, Private Sessions, Nami S.O.S, My Sweet Sister, Booby Life , Immoral Sisters, Akiba Girls, Ringetsu, among others.
It’s quite common to see big boobs in fan art; big breasted characters are very popular in doujins and fan-drawn hentai.
It is also quite common to see originally flat-chested girls with added “baggage” in fan art. This is usually just down to the artist's taste or interpretation of the character, but is sometimes done for comical effect.