Research in the nineteenth and early twentieth century established that the 
brain awakens reproduction, governs reproductive activity in the adult of 
virtually all vertebrates. By 1950, nearly 100 years later, scientists realized 
that the hypothalamus and its neurosecretory products play a key role in 
regulating gonadal function in both males and females. Another 20 years would be 
required to reveal the chemical identity of GnRH and establish that neurons 
producing GnRH represent the final common pathway through which the brain 
regulates gonadotropin secretion. It had also become clear that GnRH neurons 
behave more like motor neurons-better perhaps at going than stopping-and are 
themselves regulated by a complex network of afferent inputs, which guide the 
tempo of sexual maturation, regulate estrous and menstrual cycles, control 
seasonal breeding, and stop reproduction under adversity. In 2003, the 
revelation that kisspeptin and its receptor are critical for reproduction opened 
a floodgate of research documenting the role of kisspeptin neurons as central 
processors of reproduction. Today, there is wide consensus that kisspeptin 
signaling in the brain is essential, providing the impetus to GnRH neurons to 
awaken at puberty and reigning the activity of these neurons when discretion is 
advised. We celebrate this watershed moment-with full knowledge that time and 
discovery will provide context and perspective to even these heady days.