When is a father not a father?

Oliver Millington looks at the Court of Appeal’s decision in Re J (Loss of Parental Responsibility) [2026] EWCA Civ 344, which provides clear guidance that an unmarried man who is registered on a child’s birth certificate does not acquire parental responsibility unless he is, in law, the child’s biological/genetic father.

The Court of Appeal decision in Re J (Loss of Parental Responsibility) [2026] EWCA Civ 344[1] is a significant authority on parental responsibility, legal parentage and birth registration. It resolves conflicting first-instance decisions and establishes that an unmarried man who is registered on a child’s birth certificate does not acquire parental responsibility unless he is, in law, the child’s biological/genetic father (subject to statutory exceptions such as the Human Fertilisation and Embryology Act 2008 and adoption).  

The judgment relates to 3 conjoined private law appeals.   Each case concerned the attribution of parental responsibility and the legal status of a “father” in relation to a child.

• In Re J, the mother and the appellant were in a relationship. A child was conceived and born and the appellant was named as the father on the birth certificate. Subsequent DNA testing confirmed that he was not the child’s biological father.
• In Re M, the child was conceived by anonymous sperm donation. The appellant was named as the father on the birth certificate, but subsequent DNA testing confirmed that he was not the child’s biological father.  
• In Re P the father of the child was one of 2 identical twins with whom the mother had had a sexual relationship. DNA testing was unable to identify which of the two twins (one of whom was named as the father on the birtht certificate) was the biological father.

At paragraph 80 of the Court of Appeal’s judgment the former president McFarlane J sets out answers to the key questions the Court had to consider:

“i) The definition of ‘father’ for the purposes of CA 1989 is the common law definition and is limited to a child’s biological/genetic father. The definition does not, and cannot, extend to others who have acted as the child’s psychological/social father.

ii) Where an individual is registered as a child’s ‘father’ in their birth register entry, the parental responsibility attributed by such registration does not attach to that individual if they are not, in fact, the biological/genetic father of the child. In order for parental responsibility to be acquired by registration on a birth certificate under CA 1989, s 4, two conditions must each be fulfilled:

a) The person must be the genetic/biological father of the child; and

b) That person must be registered as ‘father’ in the child’s birth register entry;

iii + iv) Although the parties may believe otherwise, no parental responsibility is acquired at any stage by an individual who is wrongly registered as ‘father’ in a birth register entry. In consequence the question of whether parental responsibility in such circumstances is automatically terminated on the making of a declaration of non-parentage under FLA 1986, s 55A, or requires a bespoke order, simply does not arise.

[1] https://caselaw.nationalarchives.gov.uk/ewca/civ/2026/344?query=%5B2026%5D+EWCA+Civ+344 – download-options