Male Fertility · Male Factor Causes
Abstract
Human papillomaviruses (HPVs) are agents of the most common sexually transmitted diseases in females and males. Precise data about the presence, mechanism of infection and clinical significance of HPV in the male reproductive tract and especially in sperm are not available. Here we show that HPV can infect human sperm, it localizes at the equatorial region of sperm head through interaction between the HPV capsid protein L1 and syndecan-1. Sperm transfected with HPV E6/E7 genes and sperm exposed to HPV L1 capsid protein are capable to penetrate the oocyte and transfer the virus into oocytes, in which viral genes are then activated and transcribed. These data show that sperm might function as vectors for HPV transfer into the oocytes, and open new perspectives on the role of HPV infection in males and are particularly intriguing in relation to assisted reproduction techniques.
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Preimplantation genetic testing for male factor infertility: lights and shadows
Mazzilli R et al., 2026 · Journal of endocrinological investigation
Male factor could contribute, alone or in combination with female factor, to the inability to conceive in a couple in more than half of cases. The effect of male factor infertility (MFI) on embryological assisted reproductive technology (ART) outcomes remains an ongoing discussion. to evaluate the impact of MFI on embryo aneuploidy rates, to better understand the role and possible indication for Preimplantation genetic testing for aneuploidies (PGT-A), considering the role of sperm characteristics, paternal age, sperm DNA fragmentation and sperm aneuploidies. this narrative review included all available articles, published up to January 2026. Available evidence, often based on heterogeneous and old-fashioned methodologies, suggests that MFI may impair embryonic development, particularly in terms of fertilization rate and blastulation rate, more than embryo euploidy; however, a comprehensive evaluation of MFI should be integrated into clinical practice in the context of couple infertility, to also optimize the efficiency and outcomes of ART. Promising results emerged from sperm DNA fragmentation as a tool to predict embryo euploidy, but further investigations involving larger sample sizes and improved standardization are required.
Neoplastic Risk in Patients With Klinefelter Syndrome
Graziani A et al., 2026 · Andrology · Free to read
Besides gonadal involvement (hypogonadism, male factor infertility, and testicular hypotrophy), patients with Klinefelter syndrome (KS) may suffer from several extra-gonadic complications, including neoplastic events. The aim of this review is to summarize all major clinical evidence dealing with the association between KS and neoplastic diseases and provide practical suggestions for the management of patients with KS regarding neoplastic risk. This narrative review was conducted through a comprehensive search of the PubMed database, using combinations of the following keywords: "Klinefelter syndrome," "cancer," "neoplasm," "breast cancer," "germ cell tumor," "lymphoma," and "testosterone replacement therapy". KS is associated with a higher risk of breast cancer and mediastinal germ cell tumors and an apparent higher risk of hematological malignancies, in particular non-Hodgkin lymphoma and leukemia. Evidence on testicular cancer is limited, with no clear increase in risk attributable to KS, while prostate cancer has a lower risk and lower mortality rate. Given the complexity of the syndrome and the limited available evidence, regular clinical follow-up with targeted investigations when clinically indicated may facilitate early diagnosis and management of associated comorbidities.
Impact of reference gender on bone mineral density and fracture risk assessment in transgender adults
Scala A et al., 2026 · Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA · Free full text on PubMed Central
In transgender adults, reference-gender choice alters Z-scores and fracture-risk estimates. Z-scores differ by 0.4-0.6 SD, with male references identifying more individuals with low BMD for age, especially in those assigned male at birth. Dual-reference reporting is advisable until further evidence becomes available. Transgender individuals, especially those assigned male at birth (AMAB), exhibit lower bone mineral density (BMD) compared with the cisgender population. Interpretation of densitometric data is challenging, as the choice of reference gender can significantly influence Z-scores and fracture risk scores. This study aims to evaluate the impact of the gender reference database (male or female) on the assessment of BMD and fracture risk in transgender adults prior to gender-affirming hormone therapy (GAHT). We conducted a cross-sectional analysis of 249 transgender individuals (153 assigned female at birth - AFAB and 96 AMAB) aged 18-43 years, recruited in the Hospitals of Padua and Brescia (Italy). Z-scores were calculated using both male and female reference databases and FRAX scores were computed using both gender inputs. Associations with anthropometric, biochemical, and hormonal parameters were explored. Z-scores differed systematically depending on the reference gender, with mean ΔZ ranging 0.4-0.6 SD across skeletal sites. Switching reference databases frequently led to reclassification of BMD status. AMAB individuals showed a higher prevalence of low BMD for age, particularly when assessed against male references (27.1%), whereas AFAB participants generally maintained normal BMD. However, FRAX scores remained low. BMI and 25-OH vitamin D levels were independent predictors of BMD and Z-scores in AMAB individuals. The choice of reference gender significantly influences densitometric interpretation in young transgender adults. Until further evidence becomes available, calculating Z-scores using both male and female reference databases is advisable. Early preventive interventions remain essential to preserve bone health.
Predictive parameters of semen outcome improvement after varicocele treatment by scleroembolization: a retrospective study
De Toni L et al., 2026 · Journal of endocrinological investigation · Free full text on PubMed Central
Varicocele is a recognized male factor of infertility. Surgical/microsurgical correction represents a therapeutical option to improve fertility outcomes but predictive parameters for the identification who can actually benefit from varicocele correction are under investigated. Here we aimed to identify baseline predictors of semen outcome improvement after varicocele treatment by scleroembolization approach. 85 patients receiving varicocele treatment by anterograde scleroembolization (ASE, N = 42) or retrograde scleroembolization (RSE, N = 43) were retrospectively recruited. Basal and 6-months follow-up evaluation of semen, hormonal and ultrasound parameters (US) were performed to address the respective effect of varicocele treatment. In addition, basal parameters were assessed as clinical outcome predictors. Varicocele grade reduction was observed in more than 90% of patients (P < 0.001). Compared to basal, significant increase of sperm concentration (10.0 ± 9.2 × 106cells/mL vs. 23.4 ± 26.9 × 106cells/mL; P < 0.001), total sperm count (TSC 39.0 ± 54.5 × 106cells vs. 70.3 ± 90.6 × 106cells, P < 0.001) and total motile sperm count (TMS, 9.8 ± 12.8 × 106cells vs. 36.7 ± 58.1 × 106cells, P < 0.001), was observed, with no differences between RSE or ASE. All US parameters were also improved (all P < 0.001). Logistic regression analysis of basal semen and ultrasound parameters showed that basal sperm motility and left testis-mean transit time (L-MTT) were associated with TSC and TMS doubling at follow-up. However, Receiver Operating Characteristic curve analysis showed that only basal L-MTT basal sperm was consistently associated with TSC and TMS doubling at follow-up (respectively: AUC = 0.834, CI: 0.747-0.921 and AUC = 0.805, CI: 0.708-0.901; both P < 0.001). Baseline sperm count and US parameters represent useful clinical descriptors to address those subjects eligible for varicocele correction.
Related research
Testicular cancer and HPV semen infection
Garolla A et al., 2012 · Frontiers in endocrinology · Free full text on PubMed Central
Testicular cancer represents the more frequent solid tumor affecting males aged 15-35 years. In the last decades, its incidence showed a progressive increased probably due to genetic and environmental factors. Despite exposure to some viruses such as HIV, HCV, EBV, and HPV is frequently related to cancer development, there are no studies aimed to evaluate the possible implication of viral infections in the pathogenesis of testicular cancer. In this study, we analyzed sperm parameters and prevalence of HPV on sperm in 155 testicular cancer patients at diagnosis (T-1), after orchiectomy (T0) and after 12 months from surgery or from the end of adjuvant treatments (T12). All patients showed a significantly higher prevalence of semen infection than controls (9.5% and 2.4% respectively,) and altered sperm parameters both at T-1 and T0. Considering sperm parameters, at T-1 we observed a reduction of progressive motility, and after orchiectomy patients showed a reduction of sperm concentration and count and a further worsening of motility. Thereafter, patients were assigned to three groups on the basis of medical option after surgery: S = surveillance, R = radiotherapy, and C = chemotherapy +/- radiotherapy. At T12, untreated patients had an improvement of sperm parameters while R group and even more C group had a strong decrease of sperm number (p < 0.01 both vs. T0 and S group). Moreover, patients who received radio and/or chemotherapy had a very high prevalence of HPV semen infection (S = 7.7%, R = 30.8%, and C = 61.5%). In conclusion, patients with testicular cancer had frequently altered sperm parameters and higher prevalence of HPV semen infection that were worsened after radio and chemotherapy. Because HPV infection is a risk factor for cancer development and it may further reduce fertility, we suggest screening for HPV in testicular cancer patients at diagnosis and particularly after adjuvant treatments.
Sperm binding to the human zona pellucida after migration through human cervical mucus
Vigil P et al., 1995 · Int J Androl
During lactational amenorrhea a special type of cervical mucus, similar to that found during the luteal phase, is produced. This mucus, however, is able to support sperm migration. In the study described, the ability of spermatozoa to bind to the human zona pellucida (hZP) after migration through periovulatory and post-partum mucus was studied. Mucus was obtained from exclusively breastfeeding women in amenorrhea at 30, 60, 120 and 180 days post-partum. Periovulatory mucus samples from normally cycling women were used as a control. Flat capillary tubes were filled with BWW culture medium at the top and cervical mucus at the bottom. The tubes were immersed in a semen reservoir and the spermatozoa allowed to migrate through the mucus for 3 h into the culture media. Then the spermatozoa were coincubated with 3-4 hZP for 30 min and the number of bound spermatozoa per zona was counted. Periovulatory cervical mucus had an average Insler score of 14 +/- 0.5 as compared to 4.6 +/- 0.4 for post-partum mucus. Spermatozoa recovered from periovulatory mucus were always able to bind to the hZP in only 68 +/- 7% of the cases. Moreover, spermatozoa recovered from post-partum mucus bound to the ZP in lower numbers than did spermatozoa recovered fro periovulatory mucus (p < 0.03). These results suggest a greater ability of sperm-hZP binding after migration through periovulatory mucus and they also indicate that sperm binding to the ZP is possible even after sperm migration through a low quality mucus.
Human sperm-cervical mucus interaction and the ability of spermatozoa to fuse with zona-free hamster oocytes
Barros C et al., 1988 · J Reprod Fertil
Samples of semen and cervical mucus were provided by 18 couples. Cervical mucus was obtained for each day possible and stored at 4 degrees C until all the samples were collected. Flat capillary tubes were loaded with the mucous samples and spermatozoa from the husband's semen sample were allowed to migrate through the cervical mucus (3 cm column) into culture medium. The spermatozoa recovered after migration through cervical mucus were assayed in vitro with zona-free hamster oocytes. Control experiments were carried out using spermatozoa from the same semen sample but prepared by the swimming-up technique. Altogether, 557 eggs in the control group and 1236 eggs in the experimental group were analysed, and the results demonstrated that the % of sperm penetration, the mean number of sperm decondensations per penetrated egg and the mean number of spermatozoa adhering per egg all had higher values (P less than 0.05) for the control samples than for the experimental samples. We suggest that cervical mucus modifies human spermatozoa, as measured by their interaction with zona-free hamster oocytes.
HPV-related diseases in male patients: an underestimated conundrum
Garolla A et al., 2024 · Journal of endocrinological investigation · Free full text on PubMed Central
Human papillomavirus (HPV) infection is the most common sexually transmitted disease, in males and females worldwide. While the role of HPV in female diseases is well known and largely studied, males have negligibly been included in these programs, also because the proportion of women suffering and dying from HPV-related diseases is much larger than men. The aim of this review is to focus on HPV-related diseases in male patients. We performed a literature analysis on the electronic database PubMed. We considered randomized trials, observational and retrospective studies, original articles having as topic the relationship between HPV male infection and the following items: oral, anal penile cancers, warts, condylomas, male infertility, altered sperm parameters, anti-sperm antibodies (ASA). We also included experimental in vitro studies focused on the effects of HPV infection on oocyte fertilization, blastocyst development, and trophoblastic cell invasiveness. In addition, studies describing the adjuvant administration of the HPV vaccination as a possible strategy to promote HPV clearance from semen in infected males were included. Regarding head and neck HPV-related diseases, the most important non-neoplastic disease is recurrent respiratory papillomatosis (RRP). Regarding neoplastic diseases, the proportion of head and neck cancers attributable to HPV has increased dramatically worldwide. In addition, nowadays, it is thought that half of head and neck squamous cell carcinomas (HNSCCs) cases in the United States are caused by infection with high-risk HPV. HPV is noteworthy in andrological practice too. It was described as having a high HPV prevalence, ranging between 50 and 70%, in male penile shaft, glans penis/coronal sulcus, semen as well as in scrotal, perianal, and anal regions. Moreover, in male patients, HPV infection has been associated, among other diseases, with penile cancers. HPV semen infection has been reported in about 10% in men from the general population and about 16% in men with unexplained infertility, although these data seem widely underestimated according to clinical experience. In particular, HPV semen infection seems to be most related to asthenozoospermia and to anti-sperm antibodies (ASAs). HPV infection represents a health problem with a detrimental social and public impact. Despite this evidence, little has been done to date to widely promote vaccination among young males.