Lorraine Hansberry, author of A Raisin in the Sun, has three cultural identities in her personal life which are recognizable in this play. At the time of her writing, Hansberry was a young, black woman; these three aspects of Hansberry are reflected in A Raisin in the Sun.
Hansberry experienced much success early in her life; in fact, all of her success happened when she was young because she died unexpectedly at the age of thirty-five. She was the youngest playwright to win the New York Drama Critics Circle Award (and beat out Tennessee Williams and Eugene O'Neill for the honor); Hansberry understands that being young does not preclude being successful.
In the play, it is Travis and (in the end) Lena's unborn child who offer the most hope for the Youngers. The family moves to the suburbs in order to offer the children a better life; though there is certainly some risk involved, this move will ultimately offer all of them an opportunity to improve the quality of their futures. Without the children, the Youngers would never have moved or changed.
Another aspect of Hansberry's personal culture is her ethnicity. As a black woman, she would have been quite aware of the difficulties her ethnicity presented at the time of her writing, and she includes them in this play. Lena wants so much more for her family, but she is unable to provide it, no matter how hard and long she works; the only opportunity she has to make any progress happens because of her husband's death. Walter is bitter and has dreams he fears he will never have a chance to fulfill, and the news that his wife is pregnant pushes him to despair because of the hopelessness he feels about his own future.
Ruth nearly aborts her child, something completely out of character for her; but she, too, feels hopeless about the future. Beneatha does not feel hopeless like the others, but she clearly suffers from cultural confusion and ineffectually embraces both her black heritage (with Joseph Asagai) and her desire to be a modern black woman (with George Murchison). Each of these characters struggles with the same aspects of black culture that Hansberry experienced or at least observed.
The third aspect of Hansberry's cultural identity is her gender. Being a woman in the mid-1900s had challenges as well as possibilities. All three women in the play are representative of that experience. Ruth is the most traditional of the three, providing for and caring for her family the best she can, though sometimes her best is not enough. Beneatha represents the limitless possibilities (note all of her "hobbies") available to her in the constantly modernizing world; and Lena, though she is the oldest, is the one who finally takes drastic action to save her family from ruin.
Hansberry knows these characters in A Raisin in the Sun because they are all reflections or representations, in some way, of her own cultural identity.