The newborn is gradually socialized, or molded, in conformance with the family's world view and style. Introducing the new person into the system can upset the family's equilibrium, at least for a while. Whatever hinders the process is probably worth avoiding. People learn to make compromises in their family of origin. Possibilities for growth and positive change are limited when differing styles or role expectations are not accommodated.
Complementarity refers to the roles of family members as they correspond to each other.
Difficulties arise when these roles become so rigid, so narrowly defined, or so stereotyped that they no longer complement. When a family takes on a new member, whether through marriage or birth, it is important to hold onto the sense of balance that existed in the family before. Doing this means expectations and behavior may have to change. When a man standing on a floating raft shifts position, the raft may heave under his feet, but it will not sink or capsize if his movements complement the water flow and the shifting of the raft. By accommodating fluid factors, the man can keep his balance as the craft continues downriver.