Genetic Carrier Donors
At London Sperm Bank, all donors undergo thorough genetic screening to support the safety and wellbeing of future families. As part of this screening, some donors may be identified as genetic carriers. This is common and does not affect their own health, but it is important for recipients to understand what this means when selecting a donor.
This page explains what a genetic carrier is, what we screen for, and what it could mean for your treatment.
What Is a Genetic Carrier?
A genetic carrier is someone who carries a single copy of a gene associated with a specific inherited condition. Carriers do not have the condition themselves and are typically healthy with no symptoms.
A carrier only has an increased chance of passing on the condition if the other biological parent also carries a variant in the same gene.
You can read more about CMV on the NHS website.
What Do We Screen For?
Genetic testing is carried out by accredited laboratories using advanced techniques such as Next Generation Sequencing (NGS). These tests focus on identifying variants linked to common and serious inherited conditions, particularly those that are autosomal recessive or X-linked.
The following genes are included in the screening panel:
- SMN1: Linked to Spinal Muscular Atrophy (SMA)
- HBA1/HBA2: Associated with Alpha-Thalassaemia
- CFTR: Linked to Cystic Fibrosis and related disorders
- HBB: Associated with Beta-Thalassaemia and Sickle Cell Disease
- HEXA: Linked to Tay-Sachs Disease
Only gene variants that are classified as pathogenic or likely pathogenic are reported. Variants of unknown significance (VUS) are not included, as their clinical relevance is unclear.
What Does It Mean If a Donor Is a Carrier?
If a donor is found to be a carrier of any of the conditions tested, this will be clearly indicated in their donor profile under the Genetic Screening section.
Being a carrier does not affect the donor’s own health or their eligibility to donate. However, if you or your partner also carry a variant in the same gene, there could be a reproductive risk to consider.
What Are Your Next Steps as a Recipient?
If you are interested in a donor who is identified as a carrier, we recommend the following:
Speak to your fertility clinic or a genetic counsellor
They can advise on whether further screening is recommended for you or your partner.
Consider carrier screening
This may help determine whether you carry a variant in the same gene as the donor.
Understand that many patients safely use carrier donors
With proper screening and guidance, a donor who is a carrier can still be a suitable option for your treatment.
Safety, Clarity, and Compliance
All genetic screening is carried out by certified laboratories in line with UK regulatory and ethical standards. London Sperm Bank is committed to providing transparent, reliable information to support safe and informed treatment choices.
If you have any questions about a donor’s genetic status or need help understanding the results, our team is here to support you.
Have Questions About Genetic Carrier Donors?
Choosing a donor with a known genetic carrier status can feel complex — but you’re not alone. Our Clinical Genetics Team is here to provide clear, compassionate advice tailored to your circumstances. Whether you need help interpreting a donor’s report, understanding inheritance risks, or exploring your options, we’re here to guide you.