Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on hormones & fertility. Browse all Hormones & Fertility education

About one in seven couples has trouble conceiving, and a male factor contributes in roughly half of those cases. Genetics is one of the most under-discussed pieces of the picture: inherited variants can affect how many sperm a man makes, how well those sperm move, and whether they carry intact DNA. Knowing the named genes involved helps explain results that a basic semen analysis alone cannot.

How Genetics Shapes Male Fertility

Sperm production is a months-long process that depends on the right chromosomes, hormone signaling, and DNA-repair machinery all working together. When any of those steps carries an inherited change, the result can show up as a low sperm count, poor motility, abnormal shape, or elevated DNA fragmentation. Genetic factors are estimated to underlie a meaningful share of severe cases, particularly among men with very low or absent sperm counts. Identifying a genetic cause matters both for guiding care and for understanding what might be passed to children.

Y-Chromosome Microdeletions and the AZF Regions

The long arm of the Y chromosome contains three azoospermia factor regions — AZFa, AZFb, and AZFc — that house genes essential for sperm production, including the DAZ gene family. Small missing segments, called Y-chromosome microdeletions, are among the most common genetic causes of severely reduced or absent sperm. An AZFc deletion often allows some sperm production, while AZFa or AZFb deletions typically do not. Because these deletions sit on the Y chromosome, they pass to sons, which is why testing is recommended before certain assisted-reproduction procedures.

CFTR and Obstructive Causes

Variants in CFTR, the gene behind cystic fibrosis, can cause congenital bilateral absence of the vas deferens — the tubes that carry sperm. In these men, sperm are often produced normally but cannot exit. A man may carry CFTR variants without classic cystic fibrosis symptoms yet still have this reproductive form. Because a partner who also carries a CFTR variant changes the risk to a child, CFTR screening is a standard part of the genetic workup when obstruction is suspected.

Androgen Receptor and Hormone Signaling

Sperm production depends on testosterone acting through the AR gene, which encodes the androgen receptor. The AR gene contains a stretch of repeated CAG units, and the length of that repeat influences how strongly the receptor responds to testosterone. Longer repeats have been associated in some studies with reduced sperm production, though the effect is modest and context-dependent. Other hormone-pathway genes, including NR5A1 and TEX11, are linked to spermatogenic failure and are increasingly included in research panels.

Folate Metabolism, MTHFR, and Sperm DNA

Making healthy sperm requires steady DNA synthesis and methylation, both of which depend on folate. The MTHFR gene encodes an enzyme central to folate processing, and common variants such as C677T can reduce its activity. Research links impaired folate metabolism to higher sperm DNA fragmentation and altered methylation patterns, which may affect fertility and embryo quality. This is a pathway-level relationship, not a guarantee — many men with these variants father children without difficulty — but it is one reason folate status is part of the fertility conversation.

What Genetic Insight Adds — and Practical Steps

A pathway-level genetic report cannot diagnose infertility or predict conception; only a fertility specialist can evaluate that with semen analysis, hormone panels, and targeted genetic testing. What broader genetic context can do is highlight pathways — hormone signaling, folate metabolism, DNA repair — worth discussing with a provider. The PlexusDx Precision Peptide Genetic Test frames this within 14 pathways, 49 peptides, 150+ genetic insights as educational background, not a fertility diagnosis. Alongside that, evidence-based habits help: not smoking, limiting alcohol, managing weight, avoiding excess scrotal heat, and eating a nutrient-dense diet with adequate folate, zinc, and antioxidants all support sperm health.

Frequently Asked Questions About Male Fertility Genetics

Which genes are most linked to male infertility?

Y-chromosome microdeletions in the AZF regions, CFTR variants causing vas deferens absence, and androgen receptor (AR) CAG-repeat length are among the best-established genetic factors. Genes such as NR5A1, TEX11, and folate-pathway variants in MTHFR also contribute. A fertility specialist decides which targeted tests fit a given case.

Can lifestyle changes improve sperm health if genetics is involved?

Often yes. Genetics sets a baseline, but sperm are made continuously, so daily factors matter. Not smoking, moderating alcohol, keeping a healthy weight, avoiding excess heat, and getting enough folate, zinc, and antioxidants can improve semen quality over a few months, even when a genetic tendency is present. A provider can tailor recommendations.

Should I get genetic testing before fertility treatment?

Frequently, yes. Guidelines recommend Y-chromosome microdeletion and CFTR testing before certain assisted-reproduction procedures, because results can affect the approach and the chance of passing conditions to children. Your fertility specialist orders the specific clinical tests; a broad wellness genetic report is educational context, not a substitute for that workup.

Does a genetic tendency mean I cannot have children?

No. Many men with fertility-related variants conceive naturally or with assistance. A genetic finding describes a pathway tendency, not a fixed outcome. Advances in assisted reproduction, including sperm-retrieval techniques, help many couples even in severe cases. A reproductive specialist can explain what a specific finding means for your situation.

Curious how your own biology fits into this picture? Take the Precision Peptide Genetic Test to see how your DNA shapes hormone and fertility pathways across 14 pathways, 49 peptides, 150+ genetic insights — pathway-level context you and your provider can build on.

This article is part of the PlexusDx Education Hub. Browse all Hormones & Fertility education

The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use, and it does not diagnose, treat, cure, or prevent any medical condition. Consult a qualified healthcare provider before beginning any peptide protocol or making changes to your care.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.