The individual who is not the biological parent of the child or children is referred to as the stepparent.
Stepfamilies must cope with outside influences and ongoing change due to issues with the other biological parent and family members.
In addition, 50 percent of children under age 13 as of 2004 lived with one biological parent and the parent's partner.
Many other children have lived in single-parent families for a time before their biological parent remarried, when they moved into a two-parent family with one biological parent and one stepparent.
The child might refer to the adoptive parents as aunt and uncle, but people in the immediate social circle might know the child's biological parent.