They usually want the children to receive their property only if both spouses die. Single parents of young children usually want their property to be available for their children. Some property is transferred automatically at death to the person with survivorship rights. This property, called non-probate property, includes most life insurance policies and property held in joint tenancy with right of survivorship. Even if all property is non-probate property, a couple still needs wills to transfer the property in case the person with survivorship rights does not survive and to provide for the care of children.
Laws vary from state to state.
Colorado intestacy law directs that the property go to the surviving spouse if all of the children are joint children of both the husband and wife. If the children are not all mutual children, the property will be divided between the surviving spouse and the children. The proportion is determined by statute. Division of property between the surviving spouse and children may not always be desirable. With a will, the maker can indicate that all property is to go to the surviving parent, or can specify which portion should go to previous children, mutual children or stepchildren.