Background: Alfred Adler was born at Mariahilfer Strasse 208 in Rudolfsheim, then a village on the western fringes of Vienna, and today part of Rudolfsheim-Funfhaus, the 15th district of the city. He was second of the seven children of a Hungarian-born, Jewish grain merchant and his wife. Alfred's younger brother died in the bed next to him, when Alfred was only three years old. Alfred was an active, popular child and an average student who was also known for his competitive attitude toward his older brother, Sigmund.
Context: Adler's ideas regarding non-heterosexual sexuality and various social forms of deviance have long been controversial. Along with prostitution and criminality, Adler had classified 'homosexuals' as falling among the "failures of life". In 1917, he began his writings on homosexuality with a 52-page magazine, and sporadically published more thoughts throughout the rest of his life.  The Dutch psychologist Gerard J. M. van den Aardweg underlines how Alfred Adler came to his conclusions for, in 1917, Adler believed that he had established a connection between homosexuality and an inferiority complex towards one's own gender. This point of view differed from Freud's theory that homosexuality is rooted in narcissism or Jung's view of expressions of contrasexuality vis-a-vis the archetypes of the Anima and Animus.  There is evidence that Adler may have moved towards abandoning the hypothesis. Towards the end of Adler's life, in the mid-1930s, his opinion towards homosexuality began to shift. Elizabeth H. McDowell, a New York state family social worker recalls undertaking supervision with Adler on a young man who was "living in sin" with an older man in New York City. Adler asked her, "Is he happy, would you say?" "Oh yes," McDowell replied. Adler then stated, "Well, why don't we leave him alone."  According to Phyllis Bottome, who wrote Adler's Biography (after Adler himself laid upon her that task): "Homosexuality he always treated as lack of courage. These were but ways of obtaining a slight release for a physical need while avoiding a greater obligation. A transient partner of your own sex is a better known road and requires less courage than a permanent contact with an "unknown" sex. [...] Adler taught that men cannot be judged from within by their "possessions," as he used to call nerves, glands, traumas, drives et cetera, since both judge and prisoner are liable to misconstrue what is invisible and incalculable; but that he can be judged, with no danger from introspection, by how he measures up to the three common life tasks set before every human being between the cradle and the grave. Work or employment, love or marriage, social contact."
Question: What is Alfred Adler known for?

Answer:
Adler's ideas regarding non-heterosexual sexuality and various social forms of deviance have long been controversial.