By the "second sex," Simone de Beauvoir means that women are conditioned by society to understand themselves only in relation to men, whereas men are defined on their own terms. In other words, a woman's identity is defined by her relationship to a man, i.e. her husband. She traces the intellectual roots of this development through the centuries, arguing that science, religion, legal systems, and other institutions have been culpable in making women define themselves in this way. More importantly, though, she discusses how the stages that society has attached to the maturation process of women have also contributed. In short, women are made to feel like subjects or "others," a condition made even worse by marriage.