In vitro fertilization and embryo transfer: fertile areas for litigation

Is the family primarily a biologic unit composed of a fertile male, a fertile female and children who are genetically theirs, or is the family an essentially consensual unit wherein a man and a woman who are married to each other agree to have and raise children, to regard themselves and the children as a family, and to give each other the comforts of material and emotional support, regardless of any genetic nexus?