GNRH1 and central precocious puberty: Although GnRH-stimulation test is considered the ‘gold standard’ for differentiating IPP from CPP, and despite its high specificity, its sensitivity is relatively low, because occasionally IPP will progress into CPP in later times.[6,7] Moreover, there is disagreement as to the criteria for interpretation.[8] Considering pelvic ultrasound examination of the internal genitalia is rapid and non-invasive, it is important to explore its role in diagnosis and differentiation of various precocity forms.