Sir Nicholas Wall, Britain's most senior judge, has called for changes on the law on co-habitation. Unless there is a radical change in social trends - and there is no sign or reason to think there will be one - a majority of children will soon be born to unmarried couples. If that is not the case already.

So what changes are needed in response? I have always thought that the British law on divorce was very sensible. There is only one allowable reason for divorce - that the couple relationship has irretrievably broken down. But you have to say why. Permitted grounds include cruelty, desertion, unreasonable behaviour, living apart for two years with the consent of both parties, five years without consent, or adultery if that rendered common life intolerable.

Should the law on marriage be aligned? You would need to sue for marriage on the grounds that a relationship had been irretrievably established. On the grounds....kindness, reasonable mutual behaviour, after co-habitation for two years with consent, five years without consent, and after having had sex together, if that had rendered a common life tolerable....

True to the emphasis usually put on family law, Wall's concern was mainly with how money and property was distributed between co-habiting couples who had split. And yes it is true that there is an issue if a couple don't get married but otherwise have a life that corresponded to the stereotype of married life that has has not wholly died out. Namely the man continues with his career and the woman gives up her economic independence to look after him and their children. Though it can be the other way around. If the man has the house in his name too, she can suffer a serious injustice, especially if she has continuing responsibilities for the children.

So my view is that if they have lived together, and especially they have children together, they should be treated like married couples.

The Shared Parenting concern, however, is not with economic fairness between the adults; that is simply not our brief. It is with the welfare of the children. Nearly all the formal, legally required discrimination against the children of unmarried parents has now gone. But the 'Children Act' gives Judges power to do almost anything they like, provided they put in the formula that its for the best for the children. And the attitudes of some in the Family Justice system, as applied to children of unmarried parents, still hark back to the day when the problem was seen as innocent and naive girls who had been seduced and abandoned by sauve cads.

Of course some unmarried fathers are feckless and irresponsible. But some married fathers still don't pull their weight in child care either. Both groups, however now contain couples with more modern values - both parents earn and both are heavily involved in child care.

The law on co-habitation needs to put the welfare of the children as the paramount consideration. That involves deciding, first, what parenting arrangements will be best for the children. And when that is done, how best it is financed.

At present, the money comes first, and what best for the children comes second.