Regular readers of this ‘blog will recognise that certain themes or topics recur from time to time.

That is not just because they are familiar elements of the caseload handled by myself and my colleagues but due, in part, to the fact that the laws governing the work that we do can change over time.

In addition, the matters which we deal with are affected by case law. Each successive ruling becomes a precedent shaping the outcome of subsequent issues that come before us.

With that in mind, an article which I wrote a year ago might now seem particularly perceptive.

It followed a judgment in the case of a client who discovered that he was not his daughter’s biological father despite being named on her birth certificate but wished to retain Parental Responsibility (PR) for her.

In making the ruling, His Honour Judge Afzal, cited decisions handed down in several previous cases which had considered broadly similar circumstances but reached different outcomes.

I wrote that, even allowing for the fact that family law allows judges to exercise considerable discretion based on the individual details of cases, the differing conclusions gave rise to “a degree of uncertainty around the acquisition and retention of PR”.

The question of whether PR was dependent on a biological link which a father had with a child or merely being named on a birth certificate could change “if a higher court takes a different view”.

Now, within the last week or so, we have had just such a judgment, one which I feel provides much needed legal clarity but may give rise to very important potential consequences.

The decision was made in the Court of Appeal by country’s most senior family judge, Sir Andrew McFarlane and covered three separate cases in one ruling.

One case was similar to my client’s: a man sadly mistaken in the belief that he was a child’s biological father.

The second matter involved a man who knew that he wasn’t the biological father but was under the impression that he had PR by virtue of being named on the child’s birth certificate.

The third case was, in my view, highly unusual and featured a young girl now aged eight whose precise parentage could not be determined.

That was because her mother had slept with identical twins. A DNA test was inconclusive, showing only that “there was no more than each had a 50% chance of being the father, but neither was proved to be so on the balance of probabilities”.

Sir Andrew reasoned that, without a clear biological link, no Parental Responsibility could be assigned, regardless of whether someone is named on a birth certificate.

As I have been telling Jo MacFarlane, the Health Correspondent for the Mail on Sunday, his ruling is important in that it clarifies how PR should be determined.

Being told that you do not have a biological connection can be truly heartbreaking for individuals who have believed themselves to be the true parent.

That outcome has immediate and far-reaching consequences, meaning that the men concerned have no automatic say in the schooling, name or medical treatment of a child.

However, such a finding can have obvious terrible impacts for a child too, even if the non-biological parent decides to continue contributing to that child’s upbringing.

Where no definite biological link can be proven, it means a child may grow up having only a mother with parental responsibility for them unless court orders are obtained by the biological or psychological father.

Sir Andrew McFarlane’s judgment also potentially raises issues in relation to child maintenance.

There may well be men only paying support because they were ordered to do so by the Child Maintenance Service (CMS) as a result of being named on a birth certificate and not because they wanted to be involved in a child’s life.

The CMS rules state that men are presumed to be the father if they are “married to, or the civil partner of, the child’s mother at any time between the conception and birth of the child”.

It is quite possible that some men currently paying child support may now choose to take a DNA test as a result of this latest case in order to revisit those funding arrangements and seek a refund of money already paid should it turn out that they are actually not the biological parent.