In June, Kentucky will become the first state to require a presumption of equally shared parenting in child-custody cases even when one or more parents is opposed. While it's common for states to prefer joint custody when both parents are amenable, Kentucky's presumption will apply even without divorcing parents on board.

Kentucky Gov. Matt Bevin signed the measure in April, declaring that judges must presume "that joint custody and equally shared parenting time is in the best interest of the child" in almost all divorce cases. Last year, Kentucky required the same presumption for temporary child-custody cases while divorce is pending.

Exceptions exist for situations "involving an incident of domestic violence within the preceding three years" or where "there has been a domestic violence order entered" or being entered.

A Slow Shift

As of 2012, nearly half of American states stipulated a presumption or preference for joint custody in cases where parents agreed to it, according to "The Roller Coaster of Child Custody Law over the Last Half Century," published in the Journal of the American Academy of Matrimonial Law.

"A gender-neutral standard for custody was promoted by both feminists and fathers' rights groups," writes author Mary Ann Mason.

But even in states with such guidelines, old ideas about the superiority of mothers as caregivers have led to courts favoring maternal custody. Fighting for a presumption of joint custody in law and practice has been a primary goal of the fathers' rights movement.

More than 20 state legislatures in 2017 considered bills "that would encourage shared parenting or make it a legal presumption," notes The Washington Post Almost 20 related bills cropped up in 2015, too.

Despite all this attention, however, few of these bills have fared well, and those that did advanced more incremental changes (such as an Oregon law expanding the number of weekend days a non-custodial parent could visit their children) rather than creating a complete presumption of shared custody.

A 'Radical' Step?

"A presumption is a pretty radical step," Maritza Karmely of Suffolk University Law School told the Pew Research Center (PRC) in 2016. "That assumes that shared parenting works for most families, and I think that is an enormous assumption."

Pew points out that most child custody cases won't go before a judge: only about 10 percent are actually settled in court. "Cases that judges do hear are more likely to be ones in which parents can't communicate or cooperate to make decisions," it says, and "in those high-conflict situations, some researchers have warned that joint custody may be harmful to a child's well-being."

But fathers' rights activist and National Parents Organization founder Ned Holstein has repeatedly dismissed fears that joint custody laws will lead to unfit fathers raising kids.

Under the new Kentucky law, judges are still allowed to use their discretion and can decide against joint custody in cases where it's impractical or against the best interest of a child.

In other words, the shift doesn't mean that judges necessarily will grant shared custody to parents in all or most custody cases. It simply says that the state shouldn't automatically consider mothers more fit to raise children (as it did for much of the 20th century) or that fathers have more "ownership" right in children than mothers do (as was common in the era prior to supposed maternal supremacy).

America's current child custody laws "were based on the sexist belief that mothers are better than fathers at raising children," Wake Forest University psychology professor Linda Nielsen told the Post last year. "Well, the research does not support that."