A model of interactions between light and skin tissue was reviewed. For the present study the skin of newborns was examined. The characteristics of newborns skin tissue were taken into account when modeling. In the developed model the skin was introduced in three layers: the epidermis, the basal layer and the dermis. The thickness of the skin layers corresponds with the structure of newborns skin. Absorbance of each layer in the visible and near infrared regions of the spectrum was determined by the absorption of three main skin chromophores: blood, melanin and water. The formula of the scattering and absorption coefficients of blood is given in this study. This paper presents the study of the blood oxygenation effect on the signal of diffusely scattered radiation for three distances between the source and the receiver of radiation: 0.3 mm, 0.6 mm and 1.5 mm. The calculation was obtained using the Monte Carlo mathematical modeling. A detailed description of the model is given. The adequacy of the suggested model has been tested by comparing calculated characteristic with the experimental results obtained by means of double integral sphere. The results show that the wavelength range which provides sufficiently accurate measurements depends on the distance between the source and the receiver of radiation and certain data is provided. For the distance of 0.3 mm this range is at 700-780 nm, 950-1000 nm; for 0.6 mm it is at 640-670 nm, 760-780 nm, and 850-870 nm; for 1.5 mm at 620-740 nm.