A third of states earned a D+ or worse for how well their child custody statutes encourage an arrangement where children spend equal time with both parents after divorce or separation, according to a report card released Wednesday by the National Parents Organization.

Research shows that children benefit from spending equal time with each parent, the report explained. Therefore, state laws that assume equal shared parenting, even if there is nonviolent conflict between parents, help promote a child's well-being.

According to the report, children in fatherless or single-parent families represent 63% of teen suicides, 71% of high school dropouts and 90% of homeless and runaway children.

"Children's best interests are furthered by parenting plans that provide for continuing and shared parenting relationships that are safe, secure, and developmentally responsive and that also avoid a template calling for specific division of time imposed on all families," according to family law expert recommendations published by the Association of Family and Conciliation Courts in 2013, the report noted.

Since 2014 when the National Parents Organization released its first report card, 13 shared parenting bills in nine states have been signed into law. The organization defines shared parenting as an arrangement where both parents have equal responsibility for raising their child(ren). The goal is for the parents to have equal parenting time, but neither parent has less than one-third of that time.

The number of states that are considered a "shared parenting state" (meaning they earned a C grade or better) increased from 26 in 2014 to 34 in 2019, but 17 states still remain in the D or F range.

The grades were determined based on 21 factors related to each state's child custody statutes, including whether the statutes explicitly permit shared parenting, if they include a policy encouraging shared parenting and whether they express a preference for shared parenting.

Kentucky and Arizona were the only states to receive an A grade this year. Kentucky was the first state to enact an explicit rebuttable presumption of joint legal custody and equal physical custody for temporary and final court orders, according to the report. This means that joint custody (for both decision-making and time with the child) is assumed unless there is sufficient evidence supporting the need for a different arrangement.

Arizona has a "maximizing time provision," which means that the law includes a preference for "maximizing each parents time with the children," according to the report. Though states can interpret this wording differently, Arizona courts interpret it as a presumption of equal physical custody. The National Parents Organization says this interpretation could be influential for other states that have "maximizing time provisions."