Whether bras can stop breasts from developing or cause problems for breast health is a question that has been raging for more than a century, hard on the heels of concerns about how corsets compressed the lungs and abdominal organs. There are plenty of women who believe that the breasts are supported by the pectoral muscles and that wearing a bra will weaken the musculature, rather like legs weakening when we don’t walk. There is also a body of belief that bras cause a kind of toxic congestion in the breast, leading to disease — including cancer. There is no scientific support for these beliefs.
Part of the American standard is said to be based on measurements taken from servicewomen — a particular cohort of young, fit women — as they were discharged after World War II, more than half a century ago.