To state once again that Charles Darwin revolutionized the world with his theory evolution would be trite, but few consider what it has done to our most fundamental concepts of sexuality and the gender roles. Life's basic goal is to propagate itself and thus so do we. On some level, therefore, we are every one of us slaves to the popularly called "selfish gene." Is there no free will? Have we been reduced to the similarity to Darwin's model, physical imperatives making our sexual activity not at all differing from that of sea turtles? You could see it that way, but don't let determination of the gender roles depress you.
Sexual psychology - and psychology itself - was based on theories parallel to Darwin's evolution. Sigmund Freud kicked it all off, but the evolution of sexual psychology is ever-growing, one hundred fifty years after Doctor Freud. Following come sketches of a very few pioneers in the field.
Otto Rank (1884-1939) was Sigmund Freud's acolyte. Formerly a locksmith (now there's some sexual representation for you, eh?), Freud took Rank on as a secretary. The doctor soon saw Rank as a star pupil and became a father figure (Is that Freudian as well?) to the young man. One of Rank's first scientific essays took the newborn psychoanalytic theory to describe the artist's sexual psychology and the gender roles. Rank ultimately became the first non-medical analyst in the field, having received his doctorate at the University of Vienna at the tender age of twenty-eight.
In 1913, a virtual "Who's Who" of sexual psychology came together to form "The Ring" (vaginal symbolism?), which included International Psychoanalytic Association president Ernest Jones (1879-1958); Berlin Institute head Karl Abraham (1877-1925); and obligatory Hungarian genius Sandor Ferenczi (1873-1933). The Ring would go on to advance the cause of sexual psychology, affecting us still in the present day, and much of their work is cited in studies regarding the gender roles.
Alfred Adler (1870-1937), though considering himself a Freudian, reshaped many of Freud's ideas, channeling the sexual instincts in Freud's theories into feelings of inferiority. Using Freud as a model, physical problems were more taken into consideration by Adler. His publications include "The Practice and theory of Individual Psychology" and "Problems of Neurosis" in 1929.
Karen Horney (insert your own Freudian joke here). Due to personal trauma in 1911, Horney (1885-1952) herself entered psychoanalysis. She soon found herself challenging fundamental notions left over from Freud, providing valuable insight as, well, a female. Neuroticism formed the basis for much of her work.
Dr. Robert Stoller (1926-1992) did the revolutionary work on sexual fantasy and role playing beginning in the 1940s and continuing until his death. In 1968, the tome known as "Sex and Gender: On the Development of Masculinity and Feminity," a collection of theories regarding identity issues, personality definition and gender roles.