We all know that some changes to the way your breasts look are inevitable. Aging happens. But a new study has found that other factors may be at play when it comes to determining how your breasts look later in life. A new study, published in the Aesthetic Surgery Journal found that at least four external factors (as opposed to internal factors like age or genetics) have a significant impact on a woman\'s breasts. The study looked at the breasts of 161 pairs of identical twins, with an average age of 47.6 years old. Researchers took each woman\'s medical and personal history, and then photographed her breasts and subjectively rated them based on 16 aesthetic measures, including perkiness, skin quality and areola size. (As lead researcher Hooman T. Soltanian of University Hospitals Case Medical Center and Case Western Reserve University School of Medicine, told ABC News, there\'s \"no objective measurement\" of what makes breasts attractive. Thus these results are based on the researchers chosen criteria for attractiveness.) Below are four factors -- daily moisturizing, history of breast cancer, hormone replacement therapy and cigarette smoking -- that the researchers found impacted the look of a woman\'s breasts. While we all have much more to worry about than how our breasts look, it\'s nice to know some of the (huffpost)