How are Blanche and Stella in A Streetcar Named Desire opposite?

As the two are sisters, Blanche and Stella DuBois of Tennessee Williams's 1947 Broadway play, A Streetcar Named Desire, are apt foils for one another. These two members of a fallen aristocratic family from rural Mississippi find themselves in a cramped apartment in the French Quarter of New Orleans. Despite the shared fate of their family, the two women are in completely different circumstances. Stella is married to a rough man named Stanley Kowalski who is affectionate but objectifying. Blanche comes to live with Stella and Stanley in their small apartment after losing her family home in Mississippi. Tension immediately results from Blanche's polarizing personality. While both sisters have suffered the same fate involving the loss of aristocratic status and subsequent blue-collar existence, the younger Stella adapts to this change in a self-effacing and quiet way, maintaining (at least outwardly) her happiness. Blanche, however, uses manipulative tactics to deceive her friends and family (and even herself) in order to feed her already inflated ego.
Blanche is obsessed with her image and ego. Stella, on the other hand, is pregnant (and gives birth during the course of the play), thus symbolizing her implicit and utter surrender to the blue-collar but fulfilling life that Stanley provides for her. Blanche and Stanley are antagonistic from the get-go (and the relationship culminates in Stanley's angry rape of Blanche offstage while Stella is giving birth in the hospital).
During her stay in New Orleans, Blanche attracts the attention of one of Stanley's poker-playing friends, Mitch. Stanley divulges to Mitch the secret that he has uncovered surrounding Blanche's past (including the dismissal from her teaching job, which she claims to have left). Mitch, an honest and upstanding man, confronts Blanche with her past and insists that she is (contrary to her own opinion) not good enough for marriage. Mitch has a unique capacity to upset Blanche, as his disapproval is more meaningful to her than Stanley's coarse insults.
Neither woman is perfect, which makes the play more interesting and realistic; Stella passively allows Stanley to alternately strike and fondle her in exchange for a fairly comfortable and secure existence and family, while Blanche will not settle for anyone who is unable to provide ample material support and emotionally flattery to her. The play's conclusion finds Stella sitting at a poker table being fondled by her husband and Blanche duped into going to a mental hospital which (in keeping with her inflated sense of self) she believes is a cruise with a former boyfriend.