It varies from person to person, mainly genetic. Pink nipples are rare among Asians, and most of them are light brown. Individual pigment precipitation is less, and it will be a little pink. If the plastic surgery hospital does beauty, you can bleach the nipples. So color is not the basis for having children. Size is not the basis for distinguishing whether you were born or not. Nipple depression is called nipple invagination, which is a disease. Nipple size is also hereditary, but it will change a little during lactation, but if it is normal, there is no basis for identification.