Findings of a new study suggest that joint custody of children is fast becoming a norm in the United States.

A child's custody is probably the most emotionally stressful part of any divorce. Previously, mothers always got sole custody of the child because it was believed that she could take better care of her children. However, this trend seems to be changing rapidly. Keeping "the child's best interest in mind," governing bodies in the United States have become gender-neutral and encourage the involvement of both parents.

Researchers from University of Wisconsin-Madison conducted a study examining data from the Wisconsin Court Records, involving minor children in divorce cases between 1986 and 1994. They noticed a drop in the proportion of mothers granted sole custody, from 80 percent in 1986 to 74 percent in 1994. Shared custody cases rose from 7 percent to 14 percent.

"Overall, the trend away from mother-sole custody and toward shared custody is dramatic, representing a substantial change in the living situations of children of divorce over a relatively short period," Maria Cancian, lead author of the study, said in a press statement.

To further confirm the findings, researchers looked into records from 2008, which comprised of 9,873 divorce cases. They found that the percentage of mother-sole custody cases decreased from 80 percent in 1986 to only 42 percent in 2008. Equal shared custody increased from 5 percent to 27 percent in the same period. Unequal shared custody rose from 3 percent in 1986 to 18 percent in 2008.

No significant changes were observed in father-sole custody cases, though the rates dropped from 11 percent in 1988 to 9 percent in 2008. Researchers said that shared custody was more common in high income families. Age and gender of the child played no role in which parent won custody.

The study was published online in Springer's journal Demography.