Judith Wallerstein frequently is claimed by fathers' rights advocates (citing to preliminary findings with Joan Kelly that they know have been superseded) to be a supporter of joint custody. That's a misrepresentation of her position, which is pro-child, nuanced and balanced. Quotes:

Judith Wallerstein and Tony Tanke: The focus should be on strengthening the post-adjustment of the custodial parent rather than creating legal provisions that favor frequent contact between the non-custodial parent and the child. All of our work shows the centrality of the well-functioning custodial parent-child relationship as the protective factor during the post divorce years. When the court intervenes in ways that disrupt the child's relationship with the custodial parent, serious psychological harm may occur to the child as well as the parent."

Johnston, Wallerstein and Blakeslee: Joint custody and frequent visitation exchanges have been demonstrated not to further the children's post-divorce adjustment except in cases in which both parents support such a plan, and in fact, may lead to markedly worse outcomes for cases in which the tensions between parents remain high.

Wallerstein: I advocate creating a post-divorce environment that is as close as possible to life in a good intact home. The child who is happily attached to one parent is able to deal more easily and happily with the other parent.

Wallerstein: I can only conclude that joint custody as a legal presumption for all children is a misguided policy... children, especially girls, do very poorly in court ordered joint custody situations. Although our legal system is mandated to protect the best interests of the children, it often makes life harder for them.

Wallerstein: Generally, little girls are protected by close-mother daughter relationships that develop after divorce....it is the relationship that matters.

Wallerstein: The quality of the child's relationship to a nurturing parent has been established to be among the best predictors of their thriving and their ability to recover from marital conflict or parental psychopathology (Furstenburg Cherlin 1991, Johnston and Kline) Furthermore, children's post-divorce adjustment is tied to the overall quality of life in the custodial home including the creation of a nurturing, protective milieu.

Wallerstein: These needs which have been identified are accentuated for children who have experienced profound and chronic emotional distress or trauma, where the strong bond to a critical caretaker has been shown to be critical for their recovery. (Heller 1999) Graham Berman 1998).

Wallerstein: They spend hours fretting over upcoming conflicts in their schedules; this too is detrimental to their development. I have found that their anger in being "pushed around" is often long-lasting. As in intact families, parents should pay close attention to how much stress their children are experiencing.

Wallerstein: Sadly, for all children in this study, court-ordered visitation failed in its very important purpose of bringing father and children together in a renewed loving relationship. The goal was laudable; however a schedule that was never shaped to fit their needs sabotaged this ideal. In good, intact families, children are not ordered to spend major blocks of time with one parent or another on a rigid schedule in which they have no say. The father, by relying on his "rights" lost his child. How foolish we are to think that we can legislate the human heart. Our intervention is not only misguided, but may have harmed an entire generation of young people. How many are still reacting to feelings of having been bullied by their fathers and made to feel powerless? (Page 181)

Wallerstein: The American legal system is under the misguided impression that its decisions are geared toward safeguarding children, but I have rarely met a child who has felt protected by this system. The children in this study whose lives were governed by court orders all told me that they felt like second class citizens who had lost the freedoms their peers took for granted. Our court system is strangely at odds with what we experience in our own families; most households welcome input from their children. But the "court created child" is a passive vessel, like a rag doll that stays put in whatever position it is placed. The real children in this study did not remain silent about the system's unfairness. They complained about being forced by the court or by a parent backed by the court. The system is flawed. For starters, as children mature, they want their concerns heard. They don't want to be bullied. Children want a say in where they spend their summers and vacations... a time for pursuing emerging interests and spending summers with friends at home or at camp. Yet we continue to penalize children of divorce by insisting the parent's legal rights to their children will be protected.( Page 184)

Wallerstein: There are powerful lessons in these findings. When they reached adulthood, all of the children in this study who had been court ordered to visit a parent on a rigid schedule grew up angry. Most grew up very angry at the parent they were ordered to visit. All rejected the parent they were forced to visit as they got older. (Page 184)

Wallerstein: In good families, children are not ordered to spend major blocks of time with one parent or another on a rigid schedule on which they have no say; why should the children of divorce be treated with less consideration. (Page 180)

Wallerstein: Children who have been forced into court-ordered custody and visitation have grown up very angry and resentful of the parent who forced these decisions... Sadly for all children involved in this study, court-ordered visiting failed in its very important purpose in bringing father and children together in a renewed loving relationship. By relying on "his rights" the father lost her." (Page 181)

Wallerstein: One in four children in this study started using drugs and alcohol before their 14th birthday. Early sex was common in girls of divorced families. Some combine promiscuity with drugs and drinking as a way to deaden their feelings. Others are anxious to turn the tables on men; these young women were motivated by a frantic vengeance against men that was startling in its passion. The father's standards made a great difference between a woman's expectation of herself and of the men in her life. The experience of this small, select group called attention to the father daughter relationship in which the young woman feels cherished and valued. These bonds exert a powerful influence on a young woman's adult choices and their relationships with men. (Page 189)

Wallerstein: Traumatized children need to be with a parent who is able to "acknowledge, recognize and bear witness to a child's pain. Joint custody imposed over a mother's objections can interfere with the flourishing of healthy mother-daughter relationships. A strong-mother-child relationship is an important contributor to the resilience of mothers of battered women (Jaffe and Geffner), (Jaffe Hurley and Wolf)

Wallerstein: So what makes for a successful custody arrangement? In a nutshell, it depends upon the child, the parents, and how the parents treat each other. It matters whether the arrangements accurately reflect the needs and wishes of the child. Children who are ordered to traverse battlegrounds between warring parents show serious symptoms which affect their physical and mental health. The research findings on how seriously troubled these children are and how quickly their adjustment deteriorates are very powerful."

Wallerstein: The bottom line is that our studies show that the legal form of custody is not what matters, in the child's welfare. Nor is there any study that shows the amount of time spent with a parent is relevant to their psychological adjustment. No model of custody, no axiom of timesharing, no principle of greater access governs how well children do after their parents divorce. What matters most is the mental health of the parents, the quality of the parent child relationships, the degree of open anger between the parents, and the age, temperament and flexibility of the child. (Page 215)

Wallerstein: About 20% of families nationally choose joint custody. Joint custody refers to both parents having significant physical time with their children. However, joint custody does not necessarily mean equal timesharing. Everywhere I go, worried parents, mental health professionals and teachers ask "Is joint custody good for kids?" People want answers that will either reassure them that joint custody is helpful of provide the grounds for changing social policy back in favor of sole custody. Parents know that joint custody is an unproven way of bringing up children. (Page 212)

Wallerstein: The chief job of a school age child is to learn at school and to develop socially. For this reason, the child's personality and temperament need to be carefully considered. People are born with different neurological hardwiring which stays with us throughout our lives... I can only conclude that joint custody as a legal presumption for all children is a misguided policy. Although our legal system is mandated to act in the best interests of the children, it often makes life harder for them. The court emphasis on finding policies which suit all children is unrealistic and detrimental to children. We need to develop procedures that allow children to discuss their needs and wishes before visiting arrangements are made. (Page 219)

Wallerstein: School age children in intact families spend most of their time with friends and playmates in school and on the playground, not in the company of parents. Adolescents in intact families are encouraged to participate in planning their own activities. Children whose schedules are dictated by rigid court orders complain bitterly that they are treated like second-class citizens. Compared to their peers from intact homes, they have fewer rights, privileges and opportunities for social relationships and activities which could enrich their lives. (Page 313)