A custody battle between two lesbians could redefine the notion of who is a mother and perhaps force Florida lawmakers to reconsider a 19-year-old state law.

One partner donated an egg that was fertilized and implanted in the other partner, who gave birth. The Brevard County couple separated two years later.

Their fight over the now 8-year-old girl is before the Florida Supreme Court. A trial judge ruled for the birth mother and said the egg donor has no parental rights. An appellate court sided with the biological mother and said both have rights. The state Supreme Court is considering whether to hear the case.

At issue is a state law meant to regulate sperm and egg donation and constitutional questions about gay people's right to raise children.