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Written question asked by Richard Holden (Conservative) on Monday, 19 January 2026, in the House of Commons. It was due for an answer on Thursday, 22 January 2026 (named day). A holding answer was provided on Friday, 23 January 2026. A substantive answer was provided by Zubir Ahmed (Labour) on Monday, 26 January 2026 on behalf of the Department of Health and Social Care.


Marriage: Relatives

Question

To ask the Secretary of State for Health and Social Care, pursuant to the Answer of 12 January 2026 to Questions 89643, what health risks his Department has identified in relation to first cousin marriage; and whether the Department intends to publish the (a) evidence and (b) analysis informing those assessments.

Answer

The National Disease Registration Service is working with hospital trusts to continually improve the quality and completeness of data.

The Born in Bradford study provides the most definitive United Kingdom based evidence of risk of congenital anomalies. Results of this are publicly available at the following link:

https://borninbradford.nhs.uk/our-impacts/findings/?sf_paged=2

This includes a summary of health risks associated with consanguinity, specifically in Born in Bradford Evidence Briefing on Genes and health: Inheritance and Risk, available at the following link:

https://borninbradford.nhs.uk/wp-content/uploads/2023/04/HG2954-BIHR-BiB-Evidence-Briefing-Genes-and-Health-4.pdf

The Born in Bradford data indicated the risk of genetic abnormalities doubles, from 3% to 6%, in infants where parents are first cousins, similar to the increase in risk for mothers of white British origin older than 34 years old. Further information on this is available at the following link:

https://pubmed.ncbi.nlm.nih.gov/23830354/

Other publicly available academic research also indicates that miscarriage, stillbirth, and neonatal mortality are higher among consanguineous couples than non-consanguineous couples, with further information available at the following two links:

https://www.nature.com/articles/s41598-024-69151-7#:~:text=Consanguinity%20and%20spontaneous%20abortion%20and,%3C%200.001%20in%20Model%20I

https://pmc.ncbi.nlm.nih.gov/articles/PMC1508879/


Secondary information

Type
Written question
Reference
106603
Session
2024-26
Related items
Marriage: Relatives
Monday, 12 January 2026
Written questions
House of Commons
Marriage: Relatives
Tuesday, 22 September 2026
Written questions
House of Commons
Subjects
Health hazards Marriage Relatives
Link
View this Written question on www.parliament.uk