child, both parents may be more proactive in their child's upbringing, and the parents may experience less animosity and negativity in their co-parenting relationship. Parents may also communicate more effectively with each other, and they may exhibit feelings of well-being as a result of their working together to make decisions based on their child's needs. Proponents argue that it is good for children to see that their parents can work together, and over time joint legal custody has the potential to reverse some of the emotional effects of divorce on the children. Disadvantages Joint legal custody arrangements may be problematic when one parent attempts to control the majority of decisions in the child's life without regard to the other parent. Attempts to share decision-making may then cause one or both parents to become combative and argue over every decision that needs to be made about their children, resulting in significant stress to the parents and their children. Joint physical custody In joint physical custody, also known as shared parenting, the child has a legal residence or domicile in both parents' homes, and the lodging and care of the child is shared according to a court-ordered "parenting plan" or "parenting schedule"). In some states joint physical custody means equal or close to equal shared parenting time, while other states define it as an obligation to provide each of the parents with "significant periods" of parenting time so as to assure the child of "frequent and continuing contact" with both parents. For example, states such as Alabama, California, and Texas do not necessarily require joint physical custody orders to result in substantially equal parenting time, whereas states such as Arizona, Georgia, and Louisiana do require joint custody orders to result in substantially equal parenting time where feasible. Courts generally have not clearly defined what "significant periods" and "frequent and continuous contact" mean, which requires parents to litigate to find out. In some states, however, courts have provided a clear definition, for instance, in Nevada, the Supreme Court has defined joint physical custody as an arrangement where each parent has at least 40% of the parenting time on a yearly basis. Frequency In 2005/06, about 5 percent of American children ages 11 to 15 lived in a joint physical custody arrangement versus sole physical custody. Laws States tend to have one of three approaches to joint physical custody. A rebuttable presumption in favor