1. An apparatus for processing a medical image, the apparatus comprising: an image obtainer that receives a first image obtained by photographing an object; a memory that stores statistic information corresponding to the object, the statistic information including representative value of object size and the statistic information being determined based on at least one of an age including gestational age, a photographed region, and an item of the object; an image processor that calculates a scaling factor based on the statistic information and a size of the object to be displayed when the size of the object is the representative value, and generates a second image having the calculated scaling factor by adjusting a magnification of the first image; and a display that displays the second image.