I was watching vintage film entitled, As Young as You Feel (1951). Marilyn Monroe played a bit part as a secretary. She appeared remarkably unusual in the figure department. Not that I spend my spare time looking at women's busts, but it did get me thinking about how a voluptuous sex-goddess could have started out with such a normal looking body.
Marilyn began her career as a swimsuit model for Jantzen. In her early photos she was a natural brunette, but bleached her hair at age twenty. Supposedly, she tried nine different shades before settling on platinum blonde. In her first films, she was remarkably unremarkable: Love Happy, Let's Make It Legal, We're Not Married and in 1952, Monkey Business with Cary Grant and Ginger Rogers. (If you haven't seen Monkey Business, watch it!)
In 1953, we actually glimpsed her acting potential and emerging bustline in, How to Marry a Millionaire. In 1959, at the age of thirty-three, she filmed one of her best movies, Some Like It Hot. At that time, she could barely be contained in her wardrobe. (Not the closet for storing items, but her actual costumes.)
According to Celebrity Sleuth Magazine, Marilyn's vital statistics for most of her career were 37C-24-35, but she came up a little short when she was pared with Jane Russell (sporting a 38-24-36 figure) in Gentlemen Prefer Blondes (1953).
Marilyn's perceived "expansion" was prior to documented breast augmentation surgery, but who knows what they were doing in Hollywood. So, all this research and I still don't have an answer. Even more mystifying is, why I've spent all this time trying to "figure" it out?