The Children Act has sometimes been criticised for trying to do a balancing act between conflicting interests.
But the principle of children's best interests being paramount has produced some radical outcomes that reflect a cultural revolution in the way we perceive parenting.
The surprise is that it is lesbian partnerships that have successfully challenged the primacy of the traditional patriarch.
Judgements in two recent cases, now fully available on the internet, reveal just how far the legal system has moved away from the Tory government's absurd and malign representation in the 1980s of gay families as somehow not real, as 'pretend families'.
In one case, the Appeal Court this month confirmed a ruling by Mrs Justice Bracewell in a family in which two children were cared for by lesbian partners. One was the biological mother, but both shared the work of parenting, and both were perceived by the children as their parents.
After the women separated, the biological mother formed a new partnership and tried to erase the other from their life. The court had given joint responsibility, and ultimately it was the biological mother's refusal to co-operate or guarantee continuing contact with the former partner that prompted Mrs Justice Bracewell, supported by the Appeal Court, to decide that the children's interests would be best served by living not with their biological mother but with their other parent. It was not the biological status that was decisive, but her care and commitment to protecting the children's access to everyone in their family.
In the second case, which came before Mrs Justice Black in January, 'parental responsibility' was cautiously conceded to a man who had participated in helping a lesbian partnership to conceive a child. The expectation was that he would be known to the child - a father, but not a parent.
All of them, said the judge, had been 'ambushed by biology'. The father decided he wanted an equal role, and intruded inappropriately on the lesbians' family life. Ultimately, the judge awarded him parental responsibility, but only on condition that he did not intrude upon the integrity of the child's family - her lesbian parents.
The genius of these rulings is that they refuse to be 'ambushed by biology'. They support what would have been unthinkable 20 years ago: lesbians' challenge to traditional patriarchy, and children's rights vested not in biological ownership, but in the labours of love and care.
