Sexual differentiation in humans Sexual differentiation in humans Sexual differentiation in humans is the process of development of sex differences in humans. It is defined as the development of phenotypic structures consequent to the action of hormones produced following gonadal determination. Sexual differentiation includes development of different genitalia and the internal genital tracts, breasts, body hair, and plays a role in gender identification. The development of sexual differences begins with the XY sex-determination system that is present in humans, and complex mechanisms are responsible for the development of the phenotypic differences between male and female humans from an undifferentiated zygote. Females have two X
What Is Spiritism? What Is Spiritism? What Is Spiritism? ("Qu'Est-ce Que le Spiritisme" in French) is a brief introduction to Spiritism written by Allan Kardec in 1859, which is about a quarter of the length of The Spirits Book. Modern editions are augmented by a brief biography of the author, written by Henri Sausse, in 1896 which is mostly focused on his role in the History of Spiritism. The book is structured as a series of conferences about Spiritism, intended to quench the public curiosity and dismiss false notions about the doctrine. It is not intended as an initiation and is not seen