In this paper we propose an identification of morphological factors that may impact the Whole Body Specific Absorption Rate (WBSAR). The study is conducted for the case of an exposure to a front plane wave at the 2100MHz frequency carrier. This study is based on the development of different regression models for estimating the WBSAR as a function of morphological factors morphology. For this manner, a database of twelve anatomical human models (phantoms) has been considered. Also, eighteen supplementary phantoms obtained using morphing technique were generated to build the requested relation. The paper presents three models based on external morphological factors like the Body Surface Area (BSA), the Body Mass Index (BMI) or the body mass. These models show good results for families obtained by morphing technique on the estimation of the WBSAR (< 10%) but still less accurate (30%) when applied for different original phantoms. This study stresses the importance of the internal morphological factors such as muscle and fat proportions in the characterization of the WBSAR. The regression models are then improved using internal morphological factors with an estimation error around 10% on the WBSAR. Finally, this study is suited for establishing the statistical distribution of the WBSAR for a given population characterized by its morphology.