Spectrophotometry of massive star forming regions with GTC

In these latest years, the detection of Wolf-Rayet (WR) stars in Giant HII Regions (GHRs) has yielded several questions about our current understanding of massive stars evolution and hot expanding atmospheres, the age of the ionizing populations and their impact onto the physical properties of GHRs. Here, we present spectrophotometric observations of 4 extragalactic GHRs which show WR features in their spectra. Our goal is to reproduce simultaneously the observed WR properties and the emission line spectra with the help of current evolutionary synthesis models. Finally, we address the main advantages that GTC will provide to our better understanding of massive star forming regions.