Background: Reports of a secular decrease in semen quality remain controversial, particularly due to the possibility of selection bias. We aimed to describe the potential bias due to self-selection of volunteers in semen studies involving fecund men.
Methods: Using data from the French multicentre study REPRHOM, we compared the characteristics of the partners of pregnant women for three levels of participation: completion of a refusal questionnaire (n = 698), agreement to complete the study questionnaires only (n = 676) and agreement to complete the study questionnaires and give a semen sample (n = 331, 13% of the subjects approached).
Results: Poorly educated men refused more often to participate than highly educated men. Semen providers were more likely to have experienced unfavourable pregnancy outcomes (odds ratio 1.68, 95% confidence interval 1.14-2.49) compared with participants completing the questionnaires only. Time to pregnancy was similar for all participants.
Conclusions: This study demonstrates the existence of selection bias in semen studies associated with fertility and socio-demographic characteristics of men. The results of semen analysis for this population sample cannot be extrapolated to the whole population from which the volunteers originate. More information is required on who participates, and participation rates should be reported in semen studies to make it possible to interpret the results correctly.
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http://dx.doi.org/10.1093/humrep/deh521 | DOI Listing |
Ann Med
December 2025
Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive & Genetic Hospital of International Trust and Investment Corporation (CITIC)-Xiangya, Changsha, China.
Objectives: At present, most genetic tests or carrier screening are performed with blood samples, and the known carrier rate of disease-causing variants is also derived from blood. For semen donors, what is really passed on to offspring is the pathogenic variant in their sperm. This study aimed to determine whether pathogenic variants identified in the sperm of young semen donors are also present in their blood, and whether matching results for blood are consistent with results for sperm.
View Article and Find Full Text PDFZygote
January 2025
Molecular Medicine Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
Recently, the World Health Organization recommendation for abstinence time for semen analysis has been challenged in some studies and many of them have supported the advantages of a second short abstinence ejaculation. More evidence is needed to approve this for clinical use. This study aimed to compare the average routine abstinence time (2-7 days) with the short time (1-2 h) on sperm quality based on functional parameters in a population of oligo-astheno-teratozoospermia (OAT) men.
View Article and Find Full Text PDFTheriogenology
December 2024
Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China.
Sperm cryopreservation is a complex process involving gene expression, protein synthesis, membrane stability, and metabolic adaptation. However, molecular alterations in sperm cryopreservation and the mechanisms defending against freezing damage remain poorly understood. This study investigates these changes and defense mechanisms using transcriptomics, proteomics, and metabolomics data.
View Article and Find Full Text PDFSci Rep
January 2025
Dipartimento di Medicina Veterinaria e delle Produzioni Animali, Università degli Studi di Napoli Federico II, Naples, Italy.
BPV1, BPV2, BPV13, and BPV14 are all genotypes of bovine delta papillomaviruses (δPV), of which the first three cause infections in horses and are associated with equine sarcoids. However, BPV14 infection has never been reported in equine species. In this study, we examined 58 fresh and thawed commercial semen samples from healthy stallions.
View Article and Find Full Text PDFInt Urol Nephrol
January 2025
Department of Urology, Faculty of Health Sciences, Steve Biko Academic Hospital, University of Pretoria, Pretoria, South Africa.
Purpose: Contemporary antiretroviral (ARV) medications are used by millions of men for HIV treatment worldwide. Limited data exist on their direct effect on sperm motility. This pilot study hypothesizes that in vitro exposure to ARVs will reduce sperm kinematic and motility parameter values.
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