This book is designed as an advanced guide of theory for the effect of the gravity on the sagging breasts of the women. It covers the theory of the next fields: physiology of the breasts, modulus of Young, curve strain versus deformation rate, relationship models for breast Young, data table of important characteristics of the breast, table of thickness percentage of each constituent of the breast, Young's modulus of the parts of the breast as an average of a number of samples, breast size for different patients, normal tension and strain of three sensors located in different part of the breast, percentage of compression in the direction of the applied force, theoretical calculations, history of experimental model and application of the finite element models of the breast. It is included the deduction of many formulas in order to clear the concepts and to fill all needs of the students to get the fundamentals of this topic. Finally, other goal of the book is to achieve the interest and motivation of the students for this application of the Physics.