New Guidance on Capacity to Marry Under the Assisted Decision-Making (Capacity) Act 2015

In this article, Grace Ryan, Solicitor and Sarah Biggin, Trainee Solicitor examine the statutory test for capacity to marry under the Assisted Decision-Making (Capacity) Act 2015 (the “2015 Act”) and outline the key implications of the recent Circuit Court decision in AB v A Residential Centre [2025] IECC 7 for practitioners, families and professionals.

Background

The recent Circuit Court case of AB v A Residential Centre [2025] IECC 7 concerned AB, an adult with an intellectual disability living in a residential centre following his parents’ deaths. For more than 20 years, AB had been in a committed, loving and supportive relationship with CD, who also has an intellectual disability but lived independently with supports. Both AB and CD consistently expressed a wish to marry and the issue for the Court was whether AB possessed the requisite capacity to marry. The current test for capacity under the 2015 Act is that a person must be able to understand, retain, use and weigh relevant information, and communicate a decision in relation to the specific issue at hand, in this case, marriage.

Previously, the High Court had granted an interim injunction preventing AB from marrying. The injunction was later vacated but stayed pending the outcome of this capacity application.

The Applicant’s Case

The applicant, the Residential Care Centre sought a declaration under section 37(1)(b) of the 2015 Act stating that AB lacked capacity to consent to marry. The Applicant argued that:

1. The right to marry, while fundamental, is not absolute and may be lawfully restricted where capacity is lacking.
2. AB lacked the required understanding for capacity to marry. In particular, they argued that AB did not grasp that marriage may have financial consequences, such as claims arising from divorce or entitlements in relation to property.
3. AB did not understand the nature of the marriage contract, the duties and responsibilities that normally attach to marriage or that divorce may bring about financial consequences.
4. They argued that AB’s consent to the marriage was not being exercised freely and independently and that his decision to marry had been caused by external pressure or influence by the Notice Party.

AB’s Position

Counsel on behalf of AB strongly opposed the application, arguing that:

• The application represented a disproportionate interference with AB’s constitutionally protected right to marry and that he had consistently expressed a genuine wish to marry and queried why he should be treated differently from others.
• The expert assessments relied on by the applicant imposed an unrealistically high ‘perfectionist’ standard inconsistent with Irish and UK case law.
• The references to undue influence had not been substantiated in the current application and should not form part of the Court’s determination.

The Test:

The Court noted that the determination of capacity to marry is a matter of significant legal and social importance, engaging fundamental constitutional and human rights, including the right to autonomy. Judge Shannon emphasised that the 2015 Act establishes a functional, decision‑specific, and time‑specific assessment of capacity and that Section 3 of the 2015 Act is of particular relevance to the present case.  It provides that a person lacks capacity unless he or she is able to:

• Understand the information relevant to the decision;
• Retain that information long enough to make a voluntary choice
• Use or weigh that information as part of the process of making the decision
• Communicate a decision

Judge Shannon also looked at Section 8 of the 2015 Act which sets out nine guiding principles for anyone interacting with a person who has difficulties with their decision-making capacity and found that all practicable steps must be taken to support the person in making the decision before a finding of incapacity is reached, and that the person’s will and preference be given effect to, insofar as practicable.

Judgement

The consequences of such a declaration are both serious and far-reaching. It would constitute a profound intrusion into the personal autonomy and private lives of the individuals concerned.  He noted the issue that the application has required the Court to navigate the intersection of law, autonomy, and human dignity.

The Court ultimately refused to grant the declaration sought by the Applicant under section 37(1)(b) of the 2015 Act and determined that the presumption of capacity under section 8(2) of the 2015 Act had not been rebutted.

In coming to this conclusion, Judge Shannon took into account the gravity of such an interference with AB’s constitutional and personal rights, the public interest implications of making such a determination and the fact that the right to marry is protected under Article 12 of the ECHR and  Article 41.3.1 of the Constitution, which recognises the institution of marriage as the foundation of the family and pledges to guard it with special care.

The Court noted the challenge that faced the Court as there was currently no existing definitive Irish test for assessing capacity to marry. After weighing the evidence, and speaking privately to the relevant person and notice party, the Court set out a clear four‑part standard:

1. Understand the Nature of Marriage – The individual must grasp that marriage is a legally binding union that alters their civil status and creates a lifelong commitment between two people.
2. Appreciate the Duties and Responsibilities – The person must have a basic understanding that marriage entails mutual obligations, such as emotional support, companionship, and shared decision-making, even if they cannot articulate these in legal or financial terms.
3. Recognise the Potential Consequences – The individual must be aware, in general terms, that marriage may have legal and financial implications, including rights and responsibilities that arise upon separation or death. A rudimentary appreciation suffices.
4. Give Full, Free, and Informed Consent – The decision to marry must be made voluntarily, without coercion or undue influence, and with sufficient understanding of what the commitment entails.

This test reflects an intentionally low threshold and reflects that the right to marry is a fundamental constitutional right which must not be restricted unless clearly justified. The test safeguards autonomy while ensuring informed consent.

Key Implications

This judgment fills a gap in the 2015 Act by clarifying how the functional capacity test applies to marriage. Practitioners now have a judicially endorsed framework for assessing capacity in the context of marriage in a way that ensures not only the autonomy of the Relevant Person but also ensures informed consent.

Judge Shannon reinforced that the Act is both protective and empowering. Practitioners must strike a balance between safeguarding concerns and respecting the individual’s personal autonomy, particularly regarding fundamental rights like marriage. This judgment signals that denying capacity must be grounded in strong, lawful reasoning.

The Court reinforced that marriage capacity has a low threshold, focused on understanding the basic nature and responsibilities of marriage. For families and service providers, they must now ensure that any assessments respect that low threshold and do not unintentionally become barriers to the exercise of personal rights by Relevant People.

Conclusion

The AB judgment is a landmark case in Irish capacity law. It confirms that the ability to marry is governed by a functional, decision‑specific, and intentionally low‑threshold test. It also reinforces that the Assisted Decision-Making (Capacity) Act 2015 is a rights‑based statute, intended to support the autonomy of adults with cognitive impairments.

For practitioners, families, and services, this decision provides essential clarity on how to balance protection with empowerment when assisting adults wishing to marry.