Marxism was founded by Karl Marx, and, as an ideology, it made a significant impact in history. Numerous consequences of Marxist activities can still be detected. In order to understand what Marxism actually is, it is necessary to examine Marxist ideas from the very start. Development of Marxism can be noticed in moral and social phenomena. That is why we are going to examine the basic postulates of the Marxist view of the (collective) morale, in which an individual is alienated and moral norms are set by the society. Marx, Engels and their theory were supported and followed by Simone de Beauvoir, Judith Butler and many other theoreticians. They succeeded in developing Marxist ideas into something new, noticeable in the modern world – feminism and gender ideology. The Church does not and cannot accept proletariat, materialism, communism and gender ideology. Marxism had a strong, negative influence on marriage and family, offering an unlimited freedom of choice. The struggle against the Christian perception of marriage and family was supported by gender ideologists who used Marxist postulates related to marriage and family, and even took them a step further, allowing abortion, homosexuality, promiscuity, and finally, erasing bipolar gender characteristics. In order to be able to appreciate the value of marriage and family again, it is important to find out what can be read in church documents, such as Amoris laetitia, Centesimus annus and Rerum novarum, on this topic. It is crucial to understand that family is the basic component of any society, as well as our gender and identity. A man and a woman complement each other and they autotranscend in procreation. In this process the family becomes a small society and sanctuary of life in which a child becomes aware of its own dignity. It is important to provide protection for marriage and family because they are crucial for the survival of humankind.