My left breast appears to be smaller than my right breast, I would say around a cup size smaller. I'm 15 years old. Will they always be like this? Does anybody know why they are like this?
According to the theory of "Evolution by Nurtural Selection",
(often confused with Darwin's more famous Evolution by Natural Selection):
the breasts of the adolescent mammal have evolved asymmetrically in response to each individual mammal's tendency to exhibit a chiral preference for cradling infants with a particular right versus left "handedness".
This ensures that the adult mammal apportions available resources to the infant in a latitudinally-balanced manner, rather than favouring one side,
shall we say: the right,
..... until there is almost nothing left.
A competing theory: "Evolution by Natural Affection",
(likewise, on occasion, erroneously attributed to Darwin):
suggests an alternative mechanism for asymmetric mammary development,
typically preceding the arrival of the infant, by several months or more:
..... this argues that the chiral, "left versus right" attentions of the adolescent male, tend to preferentially favour one side rather than the other, thus boosting expansion of the burgeoning soft tissues, in a manner sometimes anxiously perceived by the adolescent female.
That's very normal. They probably always be that way, its just the way it is. Most woman's breasts are not the same size