In A Streetcar Named Desire, Tennessee Williams depicts sexuality as an inescapable and destructive force which benefits only heterosexual males. Each of the main characters succumbs to sexual desire in a way that suggests that humans have little to no control over their sexual impulses. When Blanche states, "Death—the opposite is desire," she establishes the proposition that as long as one is alive, he or she will act on desire. Blanche herself indulged in sexual promiscuity as a way to escape the atmosphere of death at Belle Reve created by the repeated succession to the graveyard for funerals of her dying relatives. All the characters in the play seem to give in to their sexual urges without putting up much fight. Thus Williams seems to indicate that sexuality is a normal part of life.
Although sexuality is normal, it is also destructive according to this play. Blanche's husband, Alan, kills himself because of his homosexuality. Blanche destroys her reputation by being promiscuous, and she gets fired from her job as a schoolteacher for engaging in sexual activity with one of her students. Stanley destroys Blanche's sanity—what is left of it—by acting on his sexual impulses and raping her. Mitch would also possibly have tried to force himself on Blanche in the scene when he confronts her with what he knows of her past. At least he shatters her hopes of marriage and protection. Stella's sexual desire led her to marry a boorish, selfish person and keeps her under the thumb of an uncultured, poker-playing, violent man. She is content to live a lower-class lifestyle as long as she can have those "colored lights" flashing. Stella's account of her wedding night when Stanley smashed all the light bulbs in the flat with a slipper is a metaphor for the destructiveness sexuality.
Despite the destruction it causes, sexuality can benefit some—if they are male and heterosexual. Thus Stanley faces no repercussions from forcefully using Blanche for his sexual desires. Mitch also presumably has no qualms about sex outside of marriage for himself, even as he condemns Blanche for having engaged in it. Alan, the homosexual, and Blanche and Stella, the women, are left to suffer the consequences of their sexual desires while the men, Stanley—and to a lesser degree, Mitch—can go on with their lives without feeling any negative effects.
From the experiences Williams portrays in the play, he seems to present human sexuality as inescapable, destructive, and beneficial only to male heterosexuals.