Shared parenting is advocated by feminists like Karen DeCrow:

• "Shared parenting is...the best option for women. After observing women's rights and responsibilities for more than a quarter century of feminist activism, I conclude that shared parenting is great for women, giving time and opportunity for female parents to pursue education, training, jobs, careers, professions and leisure..."
  excerpted from Syracuse New Times, 1/5/94 article by Karen DeCrow

Shared parenting is an egalitarian approach which allows each fit parent substantial time with the child. Because both parents remain involved, the children do not lose their relationship with either parent. This eliminates many "single parent" issues. Shared parenting makes sense now because the old model of a "stay-at-home mom" has been replaced by the 1990's reality that most kids have two parents who work, both before and after divorce.

Shared parenting after divorce benefits mothers.

By dividing the parental time commitment, shared parenting gives Mom time off to pursue her education, work late to advance in her career, or to enjoy some leisure. Moms with shared parenting are less stressed, and therefore better parents and workers.

Shared parenting is the best solution for children after divorce. Kids enjoy continued love and interaction with both parents, and the extended families of both parents, lessening the emotional trauma of divorce. Kids in shared parenting spend more time with a parent and less time with a paid babysitter. Kids in shared parenting arrangements have egalitarian role models. Kids also benefit from geographic stability: because the divorced parents do not move away, the children are more likely to remain in one school and to maintain their circle of friends. When neither parent is lost to a child, relationships with step parents are enhanced, because the step parent is not expected to take the place of a parent.

Presumptive shared parenting laws: The basis for such laws is simple: divorcing parents may agree to any schedule of physical time with the children. But if the parents do not agree and if both are fit, the court must allow each parent to assume as much of his or her 50% placement as they feel is best for their children.   Maximizing placement between parents allows both parents to take responsibility in raising the children and allows them to focus their energies on  working together for the benefit for the children rather than fighting each other over the children in our courts.

Can divorcing parents really work out shared parenting agreements? Yes, with education in co-parenting, and access to mediation services. 

Books which are helpful:
Mom's House, Dad's House by Isolina Ricci,
Helping Your Child Through Your Divorce by Florence Beinefeld.