Sheer Panic from child exploitation has often accompanied Hollywood movies that cast young actors as sexualized characters at their own age. When Brooke Shields played a sex trafficked prostitute at just 12 year old in the 1978 movie “Pretty Baby”, child welfare organizations “threatened to take the child actress out of her mother’s custody,”

There are several other reasons why casting directors like to cast legal adults to play teenagers roles on screen, mainly labor laws, minors can only work limited hours and need special accommodations, and puberty itself, “The lived reality of puberty does not play well on screen,” said Rebecca Feasey, who teaches gender, media, and film studies at Bath Spa University in the U.K. “This is not about aesthetics, but rather about continuity—continuity which would be challenged by developing bodies and deepening voices.”

 Slate Magazine (blog)