Breast augmentation
The modern prosthetic breast was invented in 1961, by the American plastic surgeons Thomas Cronin and Frank Gerow, and manufactured by the Dow Corning Corporation; in due course, the first augmentation mammoplasty was performed in 1962. There are five generations of medical device technology for the breast-implant models filled with silicone gel; each generation of breast prosthesis is defined by common model-manufacturing techniques.
Cleavage (breasts)
Evolutionary psychologists theorize that humans' permanently enlarged breasts, in contrast to other primates' breasts, which only enlarge during ovulation, allowed females to "solicit male attention and investment even when they are not really fertile", though Morris notes that in recent years there has been a trend toward reversing breast augmentations. According to social historian David Kunzle, waist confinement and décolletage are the primary sexualization devices of Western costume. By the turn of the 21st century, some of the attention given to cleavage and breasts started to shift to buttocks, especially in the media.