In the vast majority of cases in Arizona and elsewhere, child support is an obligation limited to biological or adoptive parents. When two people marry and bring existing children into a new family, the stepparent does not assume a default obligation to support the children if that marriage should fail. In an unusual case, one state's Supreme Court has ruled that a stepparent who aggressively pursues custody can be held liable for child support.
The case involved a man and woman and the woman's twin sons from another relationship. The stepfather assumed a role in the care of the children, and he even continued to help raise them after the couple separated in 2009. The following year the man filed for divorce. Two years after that, the woman completed her law degree and began making plans to take the children to California. At that point, the former stepfather filed a child custody action.
The court granted both parties equal physical and legal custody. Neither were permitted to move without the consent of the other party or a judge. As a result, the mother filed for child support, which two lower courts denied. Because the man was not the biological or adoptive parent of the boys, he was not obligated to make support payments.
When the matter went before the state's Supreme Court, that judicial body took a different view of the matter. Because the man had fought long and hard to establish parental rights to the children, the court found that he should also be held responsible for providing a portion of the cost of their care. This child support outcome is unusual, but it could set an important precedent that could be applied in other states across the nation, including Arizona.
Source: pennlive.com, "Stepparents who 'aggressively' fight exes for custody can be liable for child support, Pa. Supreme Court rules", Matt Miller, Dec. 29, 2015