3 March 2025
A medical study in the last year has found that genetic defects affect half of all infertility cases.(1) This brings into focus the significance of genetics for family building purposes in terms of fertility, conception, pregnancy and birth (and not just from a disease and health perspective). This can make it important to consider a range of genetic, medical and legal questions with geneticists, clinical and legal professionals. Should I undergo genetic testing to see if I might have difficulties with pregnancy or pass a genetic disorder on to my child? Should I undergo genetic counselling before conception? Should I get my embryos genetically screened before implantation? Should I undergo fertility preservation treatment? How can I maximise my chances of successful conception, birth or family completion? How can I maximise my prospects of having a genetically related child? Should I undergo prenatal testing? How can I legally protect my stored eggs, sperm and embryos? How can I successfully navigate fertility treatment law in the UK? What will happen to my stored eggs, sperm or embryos and my genetic legacy if I die?
Chromosome abnormalities in people
Abnormalities in chromosomes (structures inside cells which carry genetic information) can cause infertility. Chromosomal abnormalities can present in people in different ways including:
- Klinefelter syndrome where a male is born with an extra X sex chromosome (making them XXY instead of XY). This can result in smaller testicles, reduced sex drive, production of less testosterone and cause issues with the production of sperm as well as other physical and mental health issues. Klinefelter syndrome affects 0.1% to 0.2% of men.(2)
- Turner Syndrome, where a female is born and one of their X sex chromosomes is absent or damaged. Turner Syndrome affects around 0.04% of women and causes reduced ovarian function.(3)
- Imbalances in the structure of a chromosome, which can be passed on to a fetus and lead to an increased rate of miscarriage in pregnancy.(4)
Abnormalities in chromosomes can be identified through a form of genetic testing known as a karyotype test, which studies the size, structure and number of chromosomes in a sample of cells from your body, and identifies genetic disorders and diseases.
Chromosome abnormalities in eggs, sperm and embryos
Chromosome abnormalities in eggs, sperm and embryos can result from extra or missing copies of chromosomes and lead to unsuccessful implantation of embryos and abortion.(5)
Older age can also lead to chromosomal abnormalities in gametes and embryos. Age-related fertility decline in women is well documented, In men, there is growing understanding that older age can lead to reduced testicular function, damage to DNA in sperm and an increase in genetic mutations leading to impaired fertility or infertility.(6)
Pre-conception fertility testing can test the quality and number of eggs and sperm and assess overall reproductive health. Pre-implantation genetic testing of embryos can take different forms including: embryo biopsy, PGT-A to test for chromosome abnormalities and PGT-M genetic screening for monogenic (single gene) disorders which can be passed on.
Epigenetic abnormalities
Epigenetic abnormalities can be caused by environmental factors which affect gene expression in the body, including in eggs and sperm and early embryonic development, and which can negatively impact pregnancy and development of a fetus.(7) However, more research is required to increase understanding and awareness.
Copy number variations
Copy number variations (CNVs) occur when there are microscopic structural changes in chromosomes which can lead to infertility. A CNV variant associated with infertility in men is the microscopic deletion of a segment on the Y chromosome (azoospermia factor) which causes infertility in 10% of male fertility patients.(8) CNVs in the X chromosome are also considered a main reason for female infertility, including premature ovarian failure.(9) CNVs can be identified through genome sequencing.
Monogenic defects
Hundreds of monogenic (single gene defects) are also associated with infertility for both men and women. These can cause a range of issues impacting reproductive organs, the formation of eggs and sperm, cell division and endocrine (hormone) function.(10) For example Polycystic Ovary Syndrome (PCOS) causes fertility issues and is reported to be the most common endocrine-metabolic disorder in women of reproductive age; it causes ovulatory dysfunction and a number of genes have been associated with this.(11) Monogenic disorders can be identified in various ways including through genome sequencing, pre-implantation genetic testing and prenatal testing.
The Value of Fertility & Family Law Expertise, Advisory & Consultancy
Given ongoing advances in understanding how genetics affect fertility, declining global fertility rates, delayed family building and later-life parenthood, it is more important than ever to maximise and protect individual fertility and pathways to parenthood. Specialist fertility and family law strategies, advisory and consultancy helps inform effective approaches to (in)fertility and maximise reproductive health outcomes, as well as proactively manage family building arrangements. They identify and address a range of legal and practical issues across the family building and reproductive life cycle from pre-conception, through pregnancy, birth, family life and end-of-life, including:
- Family building options and associated legal issues due to impaired fertility including cancer diagnosis, unsuccessful conception, miscarriage, age-related fertility decline, genetic disorders, change in gender, delayed parenthood.
- Complex personal and family situations.
- Legal and practical aspects of fertility preservation.
- Navigating fertility treatment law in the UK.
- DNA and genetic testing and the law.
- Legal and practical aspects of assisted conception with an intra-family donor, known donor, anonymous/identity-release donor, co-parent or ex-partner (e.g. legal parentage, parental rights, financial responsibility and dispute mitigation).
- 3-person IVF and the law.
- Legal and wider aspects of international surrogacy or a UK surrogacy arrangement.
- Import or export of genetically matched gametes and embryos.
- Posthumous conception law and genetic legacy.
- Expert witness fertility, donor conception and surrogacy law services.
If you need to put in place effective legal and practical strategies or require advisory and consultancy to navigate fertility and pre-conception, assisted reproductive technologies, fertility treatment, global family building and effective parenting contact Louisa Ghevaert by email louisa@louisaghevaertassociates.co.uk or telephone +44 (0)20 7965 8399.
Images: Louisa Ghevaert, CEO & Founder Louisa Ghevaert Associates
Footnotes
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 Minyeon Go, Sung Han Shim, Genomic aspects in reproductive medicine, Clin Exp Reprod Med. 2024 Jun;51(2):91-101, https://pmc.ncbi.nlm.nih.gov/articles/PMC11140259/.
