text: what makes girls breasts go soft?   as women age, the composition of the connective tissue in women's breasts naturally change from being a mix of fat and fibrous connective tissue to being more fatty and less fibrous.   its this same fibrous character that makes breasts of younger women tougher to see through on mammograms!  luckily not as many young women need 'em... also, there's a ligament (cooper's suspensory ligament) that helps keep things "perky" when women are younger. ;-) lastly, good muscle tone in the chest (pectoralis) muscles helps to a certain extent.  most people lose some of this muscle tone as they age. does this answer your question?