When we talk about siblinghood we are not only referring to blood ties in families but also to social ties in different stages of life. Siblinghood can include any relationships between peers which are participative and which involve horizontal rather than hierarchical links This article will focus on the relevance of the fraternal complex. The possibility offered by fraternal links does not undermine or disturb the essential quality of the Oedipus complex. Two clinical vignettes will be presented to illustrate the influence of the fraternal complex in the shaping of psychic life.