WASHINGTON, June 6 (AP)--Disputes between parents and grandparents over what's best for children are as old as time, but one such dispute has yielded apotentially far-reaching Supreme Court ruling. Never before has the nation's highest court had so much to say aboutsomething increasingly difficult to define: the "average American family."In a 6-3 decision Monday, the court said Washington State trampled onparents' "fundamental right" to raise their families free from governmentinterference by enacting a law aimed at helping grandparents and others winvisitation rights. Just what the ruling means for grandparents-visitation laws in all 49 otherstates remains to be seen, as does its impact for non-traditional familiesthat split and turn to courts to referee battles over custody andvisitation. Steven Shapiro, national legal director of the American Civil LibertiesUnion, hailed the decision as "a victory for nontraditional familiesnationwide ... particularly significant for single-parent families, lesbianand gay and low-income parents." Ruth Harlow, deputy legal director of the Lamba Legal Defense and EducationFund, agreed. "This is a very important decision for lesbian and gay families who are atthe forefront of family law changes," she said. "The court adopted a soundmiddle course in this case, one that not only appropriately respects therights of parents but acknowledges that no hard-and-fast rule should governevery single family dispute." None of the court's six separate opinions in the Washington State casemention such families. But Justice Sandra Day O'Connor, the main opinion'sauthor, said, "The demographic changes of the past century make itdifficult to speak of an average American family. The composition offamilies varies greatly from household to household." Justice Anthony M. Kennedy, in dissent, said the "conventional nuclearfamily ... is simply not the structure or prevailing condition in manyhouseholds." Kennedy added a statement that advocates for non-traditional families aresure to seize on in future cases. "The importance of the familial relationship, to the individuals involvedand to the society, stems from the emotional attachments that derive fromthe intimacy of daily association, and from the role it plays in promoting away of life through the instruction of children as well as from the fact ofblood relationship. "Some pre-existing relationships, then, serve to identify persons who havea strong attachment to the child with the ... motivation to act in aresponsible way to ensure the child's welfare. ... In the design andelaboration of their visitation laws, states may be entitled to considerthat certain relationships are such that to avoid the risk of harm abest-interests standard can be employed by their domestic relations courtsin some circumstances." What's that mean? If up to Kennedy, even a fit and competent parent whoobjects to having someone else play a part in a child's life sometimes couldbe forced to do so--even if the person seeking visitation is not related byblood. Lawyers for adoptive parents and other non-biological caregivers already aregiving the court's latest word on family law a thorough reading. That means it likely will not be the court's last word.