Although he did not mend his ways completely, Cain did express some degree of remorse for having killed his brother Abel. G‑d therefore postponed Cain’s punishment for seven generations in order to give his descendants further opportunity to repent. Yet again, this opportunity was spurned, as demonstrated by the behavior of Cain’s descendant Lemech.
Femininity
וַיִּקַּח לוֹ לֶמֶךְ שְׁתֵּי נָשִׁים וגו': (בראשית ד:יט)
Lemech married two women. Genesis 4:19

By Lemech’s time, society had morally degenerated to the point that men were objectifying female beauty and depersonalizing women. It became customary for men to marry one woman for her beauty and a second woman for the purpose of procreation. The first wife would be given a contraceptive so that pregnancy and childbirth not mar her appearance. The husband would spend his time chiefly with her, ignoring his second wife.

Needless to say, this objectification of women goes against G‑d’s intention. G‑d created the world in such a way that all relationships consist of someone or something acting as a giver and someone or something else acting as the receiver. Both have to take the other into consideration. This is possible only because there is no absolute separation between the “giver” (male) and “receiver” (female) aspects of the relationship: Men have their female aspects and women have their male aspects. As such, each of us can and should appreciate how our spouse complements us, realizing that we have to combine our particular strengths in order to fulfill G‑d’s purpose, cherishing the contributions we each can make toward our common purpose.1