In his 1905 Three Essays on the Theory of Sexuality, Freud challenged traditional views of one's sexuality to be an inherent and predetermined fate in relation to one's gender. Karl Ulrich's and earlier thinkers, thought homosexuality to be an inborn condition within a minority of men. They speculated that a biological inheritance of certain female mental traits is responsible for making men homosexual. Freud contested that nature of one's sexuality is absent of any gender related characteristics. His contention was that all humans were initially born with a bisexual nature and the manifestation of one's sexuality is an evolutionary course of one's upbringing and interaction within their surrounding environment. In regards to. Bisexuality is what exists and heterosexuality naturalized constructed. Freud believed human as children have a polymorphous sexuality, their sexual desire is indiscriminate and varied, .
"My surprising discoveries as to the sexuality of children were made in the first instance through the analysis of adults. But later (from about 1908 onwards) it became possible to confirm them fully and in every detail by direct observations upon children. Indeed, it is so easy to convince oneself of the regular sexual activities of children that one cannot help asking in astonishment how the human race can have succeeded in overlooking the facts and in maintaining for so long the wishful legend of the asexuality of childhood." An Autobiographical Study (4214) .
Freud uses the occurrence of hermaphrodites in nature as an illustration to rationalize his bisexual theory,.
"The importance of these abnormalities lies in the unexpected fact that they facilitate our understanding of normal development. For it appears that a certain degree of anatomical hermaphrodites occurs normally. In every normal male or female individual, traces are found of the apparatus of the opposite sex.