This article tries to set up the epistemological bases of the science of ″human ecology″. This term has started to be used as a synonymous of morality, especially in the Catholic moral social doctrine that used for the first time to justify its marriage prospectives. We look at both terms together (human plus ecology) and we propose that human ecology should be a discipline that in the first time study human behavior and population (objective) using the postulates of the science of ecology (method) and then, once a conceptual framework for social sciences disciplines such as bioethics can be settle, could be used as a way to support or not moral postulates in the name of ecology. We conclude by defining which should be the methods of knowledge acquisition, the limits and the validity of what should be considered ″Human ecology″, that is to say, the ecology of the humans.