As always, the law must catch up with the changes in American life.
Under common law, a stepparent has no financial duty to support a stepchild during a marriage to that child’s natural parent. However, twenty states (Delaware, Hawaii, Iowa, Kentucky, Maine, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New York, North Carolina, North Dakota, Oklahoma, Oregon, South Dakota, Utah, Vermont and Washington) have statutes requiring a stepparent to support stepchildren. These statutes are codifications of the doctrine of in loco parentis, which holds that an adult who voluntarily acts as a parent assumes the obligation of support. Of note is the presence or absence of a noncustodial natural parent (who is usually a father) is not critical to establishing an in loco parentis obligation.
However, no statute or interpretation of in loco parentis imposes a duty on a stepparent to support a stepchild when the stepparent and stepchild no longer live as a family.
Most divorced people marry again and have additional children, natural or stepchildren, but most states do not consider stepchildren of be "’children of a subsequent marriage’" in support guidelines.
Stepparents may be awarded visitation rights with their stepchildren based on the "best interest" standard that dominates child custody and welfare actions. Twenty-three of the 50 states statutorily authorize stepparent visitation. In ten of these (California, Delaware, Kansas, Louisiana, New Hampshire, Ohio, Oregon, Tennessee, Virginia and Wisconsin) stepparents are explicitly named as having the right to request visitation. In 13 other states (Alaska, Connecticut, Georgia, Hawaii, Illinois, Maine, Michigan, Minnesota, Nebraska, New York, Texas, Washington and West Virginia) stepparents are considered "interested third parties." Five others (Arizona, Idaho, Indiana, Kentucky, Maryland and Utah) permit stepparents to petition for visitation.
Parents have a constitutionally protected right to determine a child’s "companionship, care, custody and management." Very often, however, a stepparent is given visitation rights when he or she is married to the custodial parent who dies. Custody of the child reverts to the child’s other natural parent, but the stepparent may appeal for visitation rights.
A more difficult question is awarding a stepparent custody of a child. In a divorce of a stepparent and the custodial parent, the stepparent may be granted custody when the facts demonstrate that the child would "would not benefit from being the custody of the natural parent."
Most legislatures and courts have ruled there is a strong presumption in favor of the natural parent in dispute over a child with a nonparent, including a stepparent. In these cases, even the expressed wishes of a child to remain with a stepparent are subordinate to the right of parent to his or her child.
See also In Loco Parentis.