The reason to use a reference is that it is very difficult to get human anatomy to look correct without it because, when you look at people from day to day, you automatically take in important details that help you distinguish one person from another and filter out any unimportant information, such as general anatomy. this is the reason many doll makers who sculpt from memory tend to make mistakes, especially when it comes to sculpting the face! If you keep sculpting without ever using a reference, you keep creating the same mistakes, over and over.
So doll makers, take the time to check anatomy and use a photo while sculpting. You will be surprised how quickly you will improve!