Not @ folks getting mad at facts.. The nuclear family is a byproduct of capitalism. It is a modern family structure. The nuclear family performs ideological functions for capitalism.
The nuclear family is the institution through which the wealthy pass down their private property to their children, thus reproducing class inequality. The nuclear family isn’t synonymous with a healthy family structure. The same way a multigenerational family structure isn’t.
Engles argues that the family had developed in an evolutionary way. In early societies he suggested there were no restrictions on sexual behavior.
However, over time as society became more complex restrictions were first put in place. Such as polygyny until societies reached their most advanced stage with the development of monogamy.
Engles linked this to the idea of private property as in most societies this was held by males & passed to their male heirs. Monogamy was supposed to ensure that any children born were legitimate heirs.
Engles also argues that in the earliest societies women held power. But as humans learned to herd animals men took control of livestock. So then men became the first property owners..
& Women were mere chattels of their husbands whose role was to provide their husbands with heirs & raise those children to adulthood.
& There you have it...