The Church firmly believes and teaches that men and women are co-equal partners in marriage. A Husband and Wife are equals and while the Husband is the priesthood leader of the family and head of household the Wife is also an important part of the equation.  
 
Husband and wife make decisions together for there family and each has roles to fulfill (where the roles are the traditional ones or not doesn't matter the important thing is that there is a bread winner and a home keeper) and both of these roles are vital and cannot be completed without the help of the other.  
 
You need both a mother and a father to raise a family can't it be done as a single parent yes it can but it is infinitely harder than in a two parent household.