Mind the child: what is the legal definition of ‘child’ in surrogacy cases?

The first article in this series considered the courts’ increasing scrutiny of ‘child’ and its definition for wills and trust purposes. It examined the consequences of this, including for potential claims under the Inheritance (Provision for Family and Dependants) Act 1975 (the 1975 Act).

This second article continues the discussion on the meaning of a child focusing, in particular, on the issues arising in the context of blended families and surrogacy.

Surrogacy has created a new category of risk

Surrogacy is increasingly becoming an option for family building for couples and individuals.  In a surrogacy arrangement, English law provides that:

• the surrogate mother is the child’s legal mother at birth, and if she is married/in a civil partnership her spouse, or civil partner will be the second legal parent at birth;
• if the surrogate mother is single and the intended father is the biological father of the child, he will be the second legal parent at birth; however, he will only have parental responsibility (pending a parental order being made) if he is registered on the UK birth certificate.

For intended parents to acquire legal parenthood and parental responsibility in a surrogacy arrangement, an application for a parental order must be made. To be eligible to make a parental order application, intended parents must meet certain criteria.

It may be the case that in the country of the child’s birth the intended parents are considered the child’s legal parents, while not being recognised as such in the UK. For example, where a child is born to intended parents via surrogacy in California, they will be considered the child’s legal parents at birth for US purposes; but this is not recognised in England, and the parental order process must still be undertaken.

There are frequently situations in which one, or both intended parents are the biological parents to the child born via surrogacy, however they are not considered legal parents and do not have parental responsibility pending the parental order being made. This process typically takes around six to nine months from the date of the application being issued, to the order being finalised.

Legal parenthood and parental responsibility are two separate and distinct concepts. Legal parenthood for a child can only be held by two individuals and confers an important status for the parent and child, making the child a permanent member of the parent’s family and bringing with it core responsibilities and rights. For example, entitlement on intestacy is determined by reference to legal parenthood, as are citizenship rights and the duty to maintain a child financially.

Parental responsibility is distinct from legal parenthood and is a concept that is central to all aspects concerning the welfare of children and the all-important decisions which must be made jointly by those holding parental responsibility.

Intended parents should seek advice not only in relation to their legal status for a child born via surrogacy, but, in international surrogacy arrangements, also obtain immigration guidance to ensure a smooth return to the UK and to address issues of nationality.

Implications

Questions of surrogacy and the definition of a child in relation to a trust have been recently considered in the case of Cator v Thynn [2026] EWHC 1045 (Ch). This case demonstrates that, in the context of blended families, estrangement, and a rise in surrogacy, courts are increasingly being asked to consider wider factors such as behaviour, intention, dependency, and social parenting when determining what is meant by a child.

Complexities in the specifics: old trust and will documents

Cator v Thynn involved three family trusts connected with the Longleat estate. The life tenant of the trust was the eighth Marquess of Bath, Ceawlin Henry Lazlo Thynn. His youngest child, Lord Henry Richard Isaac Thynn, had been born through surrogacy in California, although they were biologically the child of the Marquess and his wife.

The trust, however, expressly retained the pre-1970 common law meaning of family relationships. The consequence was that for the purposes of who a beneficiary of the trusts could be, a child meant a person who was themselves legitimate. There was uncertainty as to whether Henry fell into the class of beneficiaries for the trusts. An application was made to the court to determine whether the trustees could exercise a power of advancement to confer a power on the Marquess, as life tenant, to add Henry to the class of beneficiaries.

The court has recently ruled that the power of advancement may be used for that purpose. As part of this decision, the court recognised there were benefits and moral obligations to include Henry as a beneficiary (to ensure, for example, Henry’s equal treatment with other children) and that the trustees’ exercise of this power was appropriate in the circumstances and free of any conflict of interest.

Often when drafting a legacy in a will or a trust, a class gift to children, grandchildren or remoter issue will be used to benefit future generations. This is usually undertaken where future children or grandchildren may be born after the will or trust has been executed, preventing the need for such a document (or others) to be re-executed. It is important to review the definitions used in an existing will or trust to ensure they are properly understood, and reflect the intentions of those executing the document. It may be more sensible to explicitly use names of people as well as relying on class definitions.

The failure to do so, and the consequences for a family, are highlighted in the case of Marcus v Marcus [2024] EWHC 2086 (Ch) where a testator left his estate on trust to his children, believing at the time that he had two of them. However, it came to light, after the testator died, that one of the children was not biologically related to him. The court ruled that his intention had been to leave it to the two people he believed were his biological children at the time of preparing the will.

Conclusion

For clients with trust, estate, and inheritance planning considerations, private client advice should also be sought at an early stage to ensure protection.

• Wills: It is important that all parties have up to date wills, to avoid the intestacy rules having unintended consequences prior to a parental order being made. Under the intestacy rules, a child born via surrogacy is not considered ‘issue’ until the parental order is made. Intended parents should have careful regard to the definition of ‘children’ in their wills and any trust documentation, otherwise there is a risk that the surrogate child will not be recognised by default.
• Trusts: The definition in historic trusts of ‘issue’ may no longer reflect the reality of many modern family situations, if such trusts unintentionally exclude children born via surrogacy. Therefore, it is important that intended parents and trustees carefully consider the wording of both historic and any newly established trusts, to ensure that a child born via surrogacy falls within the class of beneficiaries.
• Cross border tax issues: The US remains a popular destination for intended parents entering into surrogacy arrangements. A child born in the US, including via surrogacy, is currently recognised automatically as a US citizen at birth. A surrogate child’s US citizenship should not be ignored when considering new and existing family wealth structures. This requires careful consideration to ensure that tax issues do not arise for the child in the future.
• Peerage: Children born via surrogacy do not inherit titles such as peerages of their intended parents. If titles are tied to property, issues may arise if the child is inadvertently excluded from an inheritance. This is an issue which must also be considered if there is risk that a child born via surrogacy will potentially lose out.