Because I’ve heard it many times that it is not true, yet there are 12-year-old “little girls” who have breasts like those of adult women, and take contraceptive pills.
Contraceptive pills indeed influence the size, shape, etc. of breasts since they contain hormones. It is certain that no doctor would ever prescribe contraceptive pills for a 12-year-old girl, that’s for sure. It is very unhealthy to prevent ovulation in a teenager’s body artificially, using pills administered externally, you should not even think of this.