The results of this study when considered with those of Hough et al., 2016 suggest that there is a critical period of brain development associated with the peripubertal period. For early onset GD, GnRHa is prescribed from childhood, throughout the adolescent period and into early adulthood, when an informed decision can be made about gender reassignment. This prolonged treatment that may encompass such critical developmental periods, however, may be justified by the increased risk of life-threatening behaviors (e.g. risk taking and suicide attempts), the effects of which could outweigh any minor cognitive and psychological impacts of GnRHa-treatment (Grossman and D’Augelli, 2007, Vance et al., 2014). For CPP, GnRHa-treatment commences from the time of diagnosis of early pubertal onset (8 or 9 years of age for girls or boys, respectively) and continues until approximately 11 years of age (Carel et al., 2009), with the main goal to increase predicted adult height by allowing more time for growth prior to the fusion of bones during puberty. However, this goal has been primarily achieved when GnRHa-treatment commenced with pubertal onset < 6 years of age (Carel et al., 2009, Hayes, 2016). The question then remains whether GnRHa exposure can be limited in children with pubertal onset between 6 to 8 or 9 years of age, or if GnRHa-treatment can be discontinued earlier than 11 years of age.