About

Kenneth I. Aston, PhD, is a leading researcher and clinician specializing in andrology, embryology, and the diagnosis and treatment of male infertility. He currently serves as a faculty member in the Division of Urology at University of Utah Health, where he combines cutting-edge research with compassionate patient care. Dr. Aston’s clinical and research interests focus on the optimization of fertility treatments, the development of personalized infertility care, and the discovery of novel diagnostic tools for both male and female infertility. His goal is to help patients navigate the emotional and complex journey of infertility with expert guidance and evidence-based treatment options. After completing his PhD at Utah State University in 2007, where his dissertation focused on somatic cell nuclear transfer efficiency and nuclear reprogramming, Dr. Aston joined the University of Utah's Andrology lab as a Postdoctoral Fellow. His early research experience includes working with bovine and equine nuclear transfer, and he was part of the pioneering team that successfully cloned the first equine species. In 2011, Dr. Aston was appointed to the faculty and has since become a recognized leader in the field of male reproductive health. He is the co-founder of the Genetics of Male Infertility Consortium (GEMINI) and the International Male Infertility Genomics Consortium (IMIGC)—global collaborations aimed at advancing understanding of the genetic causes of infertility. His research areas include genetics of male infertility, impact of paternal health and lifestyle on offspring outcomes, and improving sperm diagnostics and fertility treatment protocols. Dr. Aston is passionate about improving fertility outcomes through both lab-based discoveries and individualized patient care, with his team committed to achieving excellence in male fertility diagnostics to provide patients with the highest chance of success in starting a family.

Research topics

• Genetics
• Biology
• Medicine
• Bioinformatics
• Internal medicine
• Cell biology
• Surgery
• Andrology
• Computational biology
• Anatomy
• Gynecology

Selected publications

• Signatures of sex ratio distortion in humans

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-02-07 · 1 citations

  articleOpen access

  Summary Segregation distortion, the disproportionate inheritance of selfish genetic elements, is an important evolutionary force. While many species carry distorters, it is not clear if humans do. Major limitations for detecting human distortion are the small size of human families and the lack of genetic markers in most subjects. Here, we present evidence of strong distortion in a large human pedigree. We analyzed pedigrees from the Utah Population Database and identified lineages with a high chance of carrying a distorter. In particular, we identified a family that preferentially produced male offspring at a 2:1 ratio. This pattern is consistent with a distorting Y -chromosome, a rarity in species with degenerate Y -chromosomes. The detection of such non-Mendelian inheritance patterns suggests that human genomes may harbor segregation distorters.

  PublisherOA PDFDOI

• Conserved shifts in sperm small non-coding RNA profiles during mouse and human aging

  The EMBO Journal · 2026-01-20 · 2 citations

  articleOpen access

  Sperm aging impacts male fertility and offspring health, highlighting the need for reliable aging biomarkers to guide reproductive decisions. However, the molecular determinants of sperm fitness during aging remain ill-defined. Here, we profiled sperm small non-coding RNAs (sncRNAs) using PANDORA-seq, which overcomes RNA modification-induced detection bias to capture previously undetectable sncRNA species associated with mouse and human spermatozoa throughout the lifespan. We identified an "aging cliff" in mouse sperm RNA profiles-a sharp age-specific transition marked by significant shifts in genomic and mitochondrial tRNA-derived small RNAs (tsRNAs) and rRNA-derived small RNAs (rsRNAs). Notably, rsRNAs in mouse sperm heads exhibited a transformative length shift, with longer rsRNAs increasing and shorter ones decreasing with age, suggesting altered biogenesis or processing with age. Remarkably, this sperm head-specific shift in rsRNA length was consistently observed in two independent human aging cohorts. Moreover, transfecting a combination of tsRNAs and rsRNAs resembling the RNA species in aged sperm was able to induce transcriptomic changes in mouse embryonic stem cells, impacting metabolism and neurodegeneration pathways, mirroring the phenotypes observed in offspring fathered by aged sperm. These findings provide novel insights into longitudinal dynamics of sncRNAs during sperm aging, highlighting an rsRNA length shift conserved in mice and humans.

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• DESCRIBING PATTERNS OF INCREASED RISK FOR AUTISM SPECTRUM DISORDER (ASD) IN FAMILIES OF SUBFERTILE MEN USING POPULATION PEDIGREE DATA

  Fertility and Sterility · 2025-12-01

  articleOpen access
  PublisherOA PDFDOI

• Ex vivo oocyte retrieval for fertility preservation in an adolescent patient with recurrent ovarian dysgerminoma: a case report and review of the literature

  F&S Reports · 2025-01-29 · 2 citations

  articleOpen access

  Objective: To describe fertility preservation via ex vivo oocyte retrieval for an adolescent patient undergoing oophorectomy for recurrent ovarian dysgerminoma and to review the available literature regarding this technique. Design: Case report and literature review. Subjects: A 17-year-old female with a medical history of right ovarian dysgerminoma treated with oophorectomy 3 years prior, who presented with a retroperitoneal mass noted during surveillance. Biopsy of the mass and remaining ovary confirmed recurrent stage III ovarian dysgerminoma. The patient desired fertility preservation. Ovarian tissue cryopreservation and traditional transvaginal oocyte retrieval were contraindicated because of the ovarian malignancy. Exposure: The patient underwent controlled ovarian hyperstimulation with gonadotropins followed by laparotomy and left salpingo-oophorectomy 36 hours after ovulation trigger. An ex vivo retrieval of oocytes was performed under both direct visualization and ultrasound guidance in the operating room after excision of the ovary and isolated using a "mobile IVF" setup. Main Outcome Measures: Number of meiosis II oocytes cryopreserved. Results: A total of 12 meiosis II oocytes were retrieved from the ovary and were successfully cryopreserved. The patient tolerated the procedure well and has since completed chemotherapy. Conclusion: The combination of controlled ovarian hyperstimulation followed by ex vivo oocyte retrieval provides select patients with an opportunity for fertility preservation that may have otherwise faced a complete loss of fertility. In this case, the patient was able to preserve oocytes without jeopardizing her health status or delaying cancer therapy.

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• Direct identification of <i>de novo</i> mobile element insertions from single molecule sequencing of human sperm

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-10-26

  preprintOpen access

  Abstract Mobile element insertions (MEIs) are a significant source of human genetic variation, yet the rates and properties of de novo MEIs are poorly characterized due to technical limitations in sequencing technology. Here, we directly sequenced individual gametes from sperm samples of 14 donors (aged 28-62) using highly accurate PacBio long-read sequencing to identify de novo retrotransposition events without familial inference. We developed a “self-alignment” strategy using personal genome assemblies that enables high-precision, single-read detection of de novo MEIs. Using this method, we identified 51 de novo Alu insertions, revealing 7-fold variation in Alu retrotransposition rates between individuals (0.023 to 0.17 insertions/gamete). We found a significant increase in Alu activity with paternal age, yielding an additional 0.003 insertions/gamete/year, of additional paternal age, representing a direct observation of age-associated increases in structural variant (SV) mutation rates. These active Alu elements are predominantly comprised of the evolutionarily young AluYa5 and AluYb8 subfamilies and bear characteristic molecular signatures of target-primed reverse transcription (TPRT). Our population-averaged rate of 7.4 insertions per 100 gametes aligns well with previous population genetic estimates, validating both direct observation and population approaches for estimating de novo MEI rates. These results establish direct gamete sequencing as a powerful method for characterizing germline mutation processes and reveal age as a significant determinant of de novo retrotransposition in the male germline.

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• The rising role of genetics in andrology research and clinical practice

  Andrology · 2025-06-22

  editorialOpen access

  The term “androgenetics” refers to research focusing on genetics of male-specific conditions.1 For the first time, Andrology publishes a Special Issue “Genetics in Andrology” solely devoted to androgenetics—a forward-looking milestone in the field. So far, andrology has lagged behind other medical fields in taking advantage of rapid technological (r)evolution and recent breakthroughs in genetics and genomics. In this Special Issue, 10 review articles and 15 original studies authored by researchers from around the world provide a comprehensive overview of the state-of-the-art, current, and perspective clinical applications of genetics in andrology. To facilitate a broad readership, an introductory article by Akbari et al.1 is included covering the progress of androgenetics over 60 years and providing a glossary of the core terminology in medical genetics. Since the discovery that the Klinefelter syndrome phenotype is linked to 47, XXY karyotype, cytogenetic analysis has been successfully introduced to the male infertility workup, explaining 3%–4% of cases2 and adding value in clinical practice for patient counseling and management (e.g. original study by Zohdy et al. in this issue3). Access to whole-exome sequencing (WES) during the past 5–10 years has revealed the diverse landscape of monogenic infertility with over 600 proposed candidate genes.4 A thorough review by Riera-Escamilla and Nagirnaja5 including 19 WES-based studies in cohorts of unrelated cases with primary spermatogenic defects demonstrates the variability in detection rates of disease-causing variants across subphenotypes and different research settings. Across the studies, clinically relevant monogenic findings already explain 10%–20% cases of azoo/oligozoospermia and more than half of cases with 46, XY differences/disorders of sex development (DSD) or qualitative sperm defects.5-8 It is likely that the forthcoming years will bring along a further increase in the diagnostic yield of genetic infertility due to rapidly dropping costs of whole-genome sequencing (WGS). The richer information content of WGS compared with WES allows for reliable detection of genomic structural variants, as demonstrated in the original study by Khan et al.9 analyzing family cases from Pakistan. Due to high genetic and phenotypic heterogeneity, confirmation of novel gene–disease links has been a challenge. A large fraction of proposed gene–disease relationships has been reported in singleton cases or among the members of consanguineous families. To establish solid genotype-phenotype links, each finding must be confirmed in independent case(s), and their relevance to the routine clinical practice needs critical assessment. Stallmeyer et al.6 have undertaken an important task to evaluate the clinical validity of 313 candidate genes for diverse male infertility subtypes. In applying the standardized international evaluation criteria, only 70 genes with at least moderate evidence to contribute to the condition were reported. This is one step closer to routine utility of WES-based, advanced genetic testing offered by andrology clinics and infertility centers worldwide. An original study by Oud et al.10 represents another crucial contribution toward this goal, showing WES as a reliable first-tier method to simultaneously detect most common currently known genetic causes of male infertility—diverse monogenic conditions (including CFTR mutations), chromosomal abnormalities and AZF microdeletions. The diagnostic yield of this extended WES analysis already reached 23% in the clinical setting. The clinical validity of tested genes and standardized assessment of variant pathogenicity is not only important for molecular diagnostics, but also for patient management decisions. A comprehensive review by Idris et al.7 covers 46, XY DSD cases published from 2018 to 2023, highlighting broad the phenotypic variability and diverse genetics behind these conditions. The authors emphasize the essential importance of an accurate genetic finding to guide optimal clinical care for these patients across the entire life course. As another example, a review by Cavarocchi et al.8 describes how the exact molecular diagnosis in asthenoteratozoospermia cases facilitates proper genetic counseling of male infertility as a sole phenotype or in association with ciliary defects. A precise genetic diagnosis has a direct consequence to the prognosis of pregnancy outcome using intracytoplasmic sperm injection (ICSI).8, 11 A review by Caroselli et al.12 introduces preconception carrier screening (CS) to identify couples at-risk of conceiving a child affected by a severe genetic disorder. This is especially important among couples seeking infertility management to become parents. For example, in case the male partner is diagnosed with obstructive azoospermia due to biallelic CFTR mutations, the female should be also referred to testing for CFTR variants. Detection of high risk through CS allows prospective parents improved reproductive decision-making, opting for preimplantation genetic testing (PGT) to select unaffected IVF embryos, donor gametes, targeted prenatal diagnosis or adoption, or taking no actions.12 Due to ethical reasons, studies of human male gonadal biology, spermatogenesis and implicated genes have been limited to only a few methodological options, such as histopathological analyses of available testicular biopsies. Mahyari et al. has innovatively used this material to develop a high-dimensional transcriptional atlas of the human testis at the single cell level.13 A review by Xu and Chen introduces spatial transcriptomics (ST)14 as a novel tool to dissect the complicated process of spermatogenesis and discusses how ST has been leveraged to identify spatially variable genes, characterize cellular neighborhood, delineate cell‒cell communications, and detect molecular changes under pathological conditions in the mammalian testis. Research on knockout (KO), transgenic, and other types of mouse models has been an indispensable tool to identify and characterize hundreds of genes required for male fertility and reproductive health. An excellent review by Singh and Schimenti15 summarizes the current outcomes and challenges in using mouse models (as a proxy to human) in reproductive biomedicine for gene discovery, functional dissection of molecular pathways, modeling putative human infertility variants, identifying contraceptive targets, and developing in vitro gametogenesis. Several papers in this Special Issue further illustrate the value of murine research to understand human reproductive conditions. For example, Yin et al.16 have summarized complementary literature from human and mouse showing the essential role of telomeres in male meiosis and Jorgez et al.17 have developed transgenic mice lacking Kctd13 to study penile development and rescue of micropenis. Clinically actionable genetic testing of male-specific conditions is not limited to infertility diagnostics and respective management decisions. Basic research and clinical implications for male-specific cancers and their comorbidities represent another expanding area in andrology. Furthermore, a recent study has shown almost fivefold enrichment of disease-causing findings in hereditary cancer genes in infertile compared with fertile men, suggesting shared genetic etiologies.18 Prostate cancer is the most common malignancy in men, affecting one in eight subjects. A narrative review by Chou et al.19 summarizes hereditary conditions and syndromes predisposing to prostate cancer, indications for germline testing, incorporation of genetic data at different phases of cancer prevention and management, such as screening, monitoring, and treatment. Other common male-specific cancers are testicular germ cell tumors (TGCT) affecting young men due to congenital defects of testis development. Original research by Gayer et al.20 describes the generated murine model of pure teratomas that can be effectively used for preclinical research of TGCT. In summary, it is exciting to acknowledge the growing extent, diversity, and depth of androgenetics research worldwide, and its increasing role in improving clinical practice and patient management. This Special Issue has significantly contributed to highlight the current and long-term perspectives of genetics in andrology. Maris Laan conceptualized and drafted the manuscript, and Donald F. Conrad and Kenneth I. Aston contributed to the critical commenting and editing of the material. All the authors reviewed and approved the final version. Maris Laan is supported by the Estonian Research Council, grant PRG1021. This work was supported by grants from the United States NIH, including R01HD078641 and P50HD096723. Donald F. Conrad is supported by the National Institute of Health Office of Directors (NIH/OD) Grant P51 OD011092 (to the Oregon National Primate Research Center). The authors declare no conflicts of interest.

  PublisherOA PDFDOI

• Genetic and epigenetic landscape of male infertility

  Trends in Genetics · 2025-08-21 · 10 citations

  reviewOpen accessSenior author
  PublisherOA PDFDOI

• Risk of mortality in family members of men seeking fertility assessment

  Fertility and Sterility · 2025-07-15 · 2 citations

  articleOpen access
  PublisherOA PDFDOI

• SAT-158 Azoospermia/Oligozoospermia and Prostate Cancer are Increased in Families of Women with Primary Ovarian Insufficiency

  Journal of the Endocrine Society · 2025-10-01

  articleOpen access

  Abstract Disclosure: K. Allen-Brady: None. S. Kodoma: None. L.E. Verrilli: None. J.M. Ransay: None. E.B. Johnstone: None. J.J. Horns: None. B.R. Emery: None. L. Cannon-Albright: None. K.I. Aston: None. J.M. Hotaling: None. C.K. Welt: None. Background: Nonobstructive azoospermia (NOA) and primary ovarian insufficiency (POI) have common genetics that may also predispose to cancer risk. Objectives: We hypothesized that NOA or severe oligozoospermia and risk of male cancers would be higher in families of women with POI. Methods: Women with POI were identified using International Classification of Disease codes in electronic medical records (1995-2021) from two major healthcare systems in Utah and reviewed for accuracy. Using genealogy information in the Utah Population Database, women with POI (n=392) and their relatives were included if there were at least three generations of ancestors available. Men with NOA or severe oligozoospermia (≤5 million/mL) from the Subfertility Health and Assisted Reproduction and the Environment Study were identified in these families and risk was calculated in relatives compared to population rates. The relative risk of prostate and testicular cancer was examined using the Utah Cancer Registry. Results: There was an increased risk of NOA/severe oligozoospermia in relatives of women with POI among first- (RR 2.8 [95% CI 1.1, 6.7]; p=0.03), second- (3.1 [1.1, 6.7]; p=0.02), and third-degree relatives (1.8 [1.1, 3.1]; p=0.03). There was evidence for an X chromosome translocation, an autosome inversion and autoimmune polyglandular syndrome as a cause for POI and NOA in three families. In the families with POI and NOA/oligozoospermia (n=21), prostate cancer risk was higher in first- (3.5 [1.1, 8.1]; p=0.016) and second-degree relatives (3.1 [1.9, 4.8]; p=0.000008). Conclusions: The data demonstrate excess familial clustering of severe spermatogenic impairment compared to matched population rates, along with higher prostate cancer risk in relatives of women with POI. These findings support a common genetic contribution to POI, spermatogenic impairment and prostate cancer. Presentation: Saturday, July 12, 2025

  PublisherOA PDFDOI

• Genetic and genomic insights into male reproductive tract development

  Fertility and Sterility · 2025-04-01

  review
  PublisherDOI

Recent grants

• Sperm sample preparation for point of care applications

  NIH · $1.2M · 2018–2022

• Transgenerational Effects of Smoking-Induced Changes to Sperm DNA Methylation

  NIH · $615k · 2015–2018

• Genomics of spermatogenic impairment

  NIH · $5.7M · 2014–2027

Frequent coauthors

• Douglas T. Carrell

  University of Utah

  110 shared

• James M. Hotaling

  University of Utah

  83 shared

• Donald F. Conrad

  Oregon Health & Science University

  71 shared

• Liina Nagirnaja

  Oregon Health & Science University

  65 shared

• Timothy G. Jenkins

  60 shared

• Alexandra M. Lopes

  Universidade do Porto

  42 shared

• Benjamin R. Emery

  University of Utah

  39 shared

• Bradley R. Cairns

  University of Utah

  32 shared

Labs

• University of Utah Health - Andrology LabPI

Education

• Ph.D., Somatic cell nuclear transfer efficiency and nuclear reprogramming

  Utah State University

  2007

Awards & honors

• Genetics of Male Infertility Consortium (GEMINI) (co-founder…
• International Male Infertility Genomics Consortium (IMIGC) (…