In this contribution I present my current work on a new generation of evolutionary synthesis models that compute the multiwavelength energy distribution (from gamma rays to radio) as well as the associated dispersion for young stellar systems. I will also show some statistical effects that may appear in the analysis of surveys, such as bimodal or multimodal distributions and bias when color indices computed by the codes are compared with observations. Such a new generation of synthesis models may be useful for the analysis of the data expected from the GTC.