One of the most interesting ways a mother contributes to the development of her child - by helping her husband be a better father:

... mothers influence how fathers provide their essential contributions to children’s development. Andrea Doucet’s recent analysis of caregiving found that fathers nurture development in ways that are unique to mothers by focusing on play to connect, fostering independence, promoting problem solving, and encouraging risk taking, among other things (Doucet, 2006). Mothers influence how fathers enact their caregiving through the quality of their relationship with fathers and in how they view fathers’ contributions. Fathers in turn, enable mothers to provide essential contributions to their child’s development by caring for mothers emotionally and physically. A father’s emotional care of his wife strengthens her maternal sensitivity and reduces her maternal stress, enabling her to nurture more effectively. -- Dr. Jenet Erickson writing at Love & Fidelity Network