Importantly, differences in the immune systems of males and females have been observed as early as in the first few years of life, suggesting a developmental component to sex-specific differences in disease risk17. Such differences could result in sex-specific thresholds of susceptibility to immune-mediated diseases throughout life. Interestingly, immune responses may be modulated by sex hormones18,19. In fact, the transient rise in sex steroid levels (‘minipuberty’) that occurs in early infancy1 (Figure 1), could pattern immune cells differently in boys and girls. Thus, both the immune and endocrine systems likely contribute to sexual dimorphism in the epidemiology of many common diseases. However, recent evidence suggests that some of the differences between males and females may also be due to differences in genetic architecture. The review henceforth will focus on such sex-specific genetic effects.
