A parent is a caretaker of the offspring in their own species. In humans, a parent is of a child (where "child" refers to offspring, not necessarily age). A biological parent consists of a person whose gamete resulted in a child, a male through his sperm, and a woman through her ovum. Parents are first-degree relatives and have 50% genetic overlap. A woman can also become a parent through surrogacy. However, some parents may not be biologically related to their children. An adoptive parent is one who nurtures and raises the offspring of the biological parents but is not actually biologically related to the child. Children without adoptive parents can be raised by their grandparents or other family members.