This work aims to characterize religious and secular moralities in the West from a critical-diachronic point of view, seeking to identify spaces that cover moral relativism in solving complex bioethics issues. Concerns such as the destination of surplus embryos, for instance, usually raise polarized positionings without consensual solutions. With the presuppositions introduced on western culture through several events, mainly the principle of laicity, the view of morality widened. This work is reflexive, meta-ethical, with an interdisciplinary approach. It is a national and international literature review regarding the main points on religious and secular morality. We concluded that the present moral overview certainly includes moral relativism based on essential morality, one which can be represented by moral strangers and moral friends.