In the course of the twentieth century cosmetic procedures began to play an ever larger role in plastic surgery. Previously plastic surgery had been the science of physical restoration and breast prostheses were used mainly to replace the surgically amputated breast. This breast removal, also called mastectomy, was sometimes necessary to remove a malignant tumour. In the second half of the twentieth century the shape and size of the breasts were bound up with the prevailing ideal of beauty. Since opinions on the ideal female shapes could change it happened that inserted implants were removed after a number of years, because the model had changed and naturally shaped breasts were preferred. If in women it was the breasts that determined the ideal of beauty, in men the efficient mechanical functioning of the sexual organ was the measure of happiness. Consequently in the course of time a great variety of penis implants came on the market, which, for example, could simulate an erection through bending.