By examining the story of the "dudaim", we notice Yaakov's complex familial relationships: the parent-child relationships of Leah and her children, and the husband-wife relationship of Yaakov and Rachel. While Rachel and Leah may have thought that these relationships may be bartered and exchanged, the "dudaim" story teaches us that in fact this is not the case. 

Yemei Iyun be-Tanakh