During the 1940s and 1950s, western media created a "mammary fixation" that shaped teen perceptions of breast size. Popular American culture in the 1950s was notable for its focus on full-breasted women like Lana Turner and Jane Russell. The emphasis on the female figure came from several sources: girls wanted bras at an earlier age than ever before, while their mothers felt they should help their daughters develop a "good" figure; doctors who valued maternity over all other female roles; and companies who saw a profit in persuading girls and their parents that adolescent breasts needed support. In some social circles, a girl's ability to fill a bra became central to her status and sense of self.
It became common in the 1950s for pre-teen girls in the United States to begin wearing training bras even though their breasts were too small to actually require support. The American Academy of Pediatricians published Puberty: Information for Boys and Girls in 2002. In it, they advised girls:
As your breasts develop, you may need a bra. Some girls feel that wearing a bra for the first time is exciting—it is the first step toward becoming a woman! However, some girls feel embarrassed, especially if they are among the first of their friends to need a bra. If the people around you make a bigger deal of your first bra than you would like, try to remember that they do not mean to embarrass you, they are just proud of how much you have grown.
The author points out that young girls are socialized to be more concerned about what other people think about their wearing a bra rather than their own feelings. As a result, young girls may be anxious to acquire their first training bra before their breasts actually need support, if only for social purposes. Girls are then faced with the challenge of keeping current and wearing the latest, fashionable bra. Some young girls avoid wearing a bra, fearing an end to their childhood freedoms, such as going topless. Girls who develop breasts earlier than their peers may be sensitive to comments and teasing. Because bras are built to manufacturers' standards, if the girl's body does not conform to the shape and size of the bra, she may blame herself.
Firm, upright breasts are typical of youth. As such, they may not physically require the support of a bra. A pencil test, developed by Ann Landers, has sometimes been promoted as a criterion to determine whether a girl should begin wearing a bra: a pencil is placed under the breast, and if it stays in place by itself, then wearing a bra is recommended; if it falls to the ground, it is not.
Oleg Cassini made a provocative "Room at the Top Bra" in nylon and Lycra spandex for Peter Pan. In the early 1960s, bra makers marketed to girls 13–19, and later in '60s they targeted pre-teen girls age 10–12. New labels like Teenform, Teencharm, and Heaventeen catered to their market. Some companies' advertisements showed girls waist up wearing only a bra. Mercy Dobell, editor of Corset and Underwear Review, wrote that "the bra has joined lipstick and 'heels' in becoming one of the beloved symbols of growing up. Mass media encourages teens and tweens to begin wearing lingerie at a younger age, before or as soon as their breasts begin to develop, as a way to advertise their sexuality.