Swiss theologian Emil Brunner (1899-1966) developed a liberal Protestant theology of the family, contrary to the more traditional biblical views of his compatriot Karl Barth. Brunner treated the family as a natural order of creation, alongside the state and economy. The family has a natural monogamous structure and a built-in set of spousal and parental rights and duties that cannot be invaded by other social spheres or reconstructed by family members or liberal reformers. The state has to protect and enforce these family rights and duties as a matter of justice, but Christians should honor them spontaneously in expression of agapic love. Brunner prized children and their rights, and he called the union of husband, wife, and child, a “trinitarian union” built on the foundation of mutual natural attraction and as a reflection of the triune Godhead. But he insisted that marital sex was a unique expression of love not just a means to a procreative end, and he firmly rejected as unrealistic the procreative perfectionism of some parts of the Catholic tradition. A marital couple without children was a complete family, he believed, just as a widow(er) or divorcee with children remained a complete family
