Journal ArticleDOI
Declining sperm count and fertility in males: An epidemiological controversy
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TLDR
These findings are inconsistent with the reports that male infertility rates have remained constant during the past 3 decades, and the increased number of men seeking consultation on infertility may only be the result of the tendency of couples to delay pregnancy and the increase availability of treatment.Abstract:
There have been several suggestions from different populations that sperm count has decreased in the past 20 years. Concerns have, however, been raised in the interpretation of these findings, particularly with regards to subject selection mechanisms and data-analysis. Furthermore, these findings are inconsistent with the reports that male infertility rates have remained constant during the past 3 decades. The increased number of men seeking consultation on infertility may only be the result of the tendency of couples to delay pregnancy and the increased availability of treatment. Moreover, sperm concentration is not always in itself the determinant of male fertility, so the use of sperm count as an indicator of male infertility in epidemiological studies should be considered with caution.read more
Citations
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Paternal contribution: new insights and future challenges
TL;DR: To tackle some of the misconceptions surrounding the paternal contribution, the factors that are actually delivered by the sperm at fertilization and their potential developmental functions will be discussed using data from humans and animal models.
Journal ArticleDOI
The epidemiology of multiple births
Renata Bortolus,Fabio Parazzini,Liliane Chatenoud,Guido Benzi,Massimiliano Bianchi,Alberto Marini +5 more
TL;DR: The constant frequency of monozygotic (MZ) pregnancies over time and in different geographical areas suggests that the determination of MZ twins is largely unchanged over time, and that a genetic mechanism may have a role.
Journal ArticleDOI
RNA in human sperm.
TL;DR: Irrespective of their role in the embryo, their use as a means to assess male factor infertility is promising and it remains tempting to analogize them to maternally-derived transcripts active in early embryo patterning.
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The effects of inbreeding on testicular sperm concentration in Peromyscus polionotus.
Susan W. Margulis,Allison Walsh +1 more
TL;DR: The declines in testicular sperm concentration found here suggest that inbreeding can affect fertility in adult males, and could provide a mechanism to monitor potential declines in reproductive performance before population-level reproductive success is irreparably impaired.
Journal ArticleDOI
Sperm protection in the male reproductive tract by Toll-like receptors.
S Saeidi,F Shapouri,Elham Amirchaghmaghi,H Hoseinifar,Marjan Sabbaghian,Sadighi Gilani,Allan A. Pacey,Reza Aflatoonian +7 more
TL;DR: It could be concluded that TLRs may provide a broad spectrum of protection from infection in the male reproductive tract and may influence on the developmental process during spermatogenesis.
References
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Journal ArticleDOI
Evidence for decreasing quality of semen during past 50 years.
TL;DR: There has been a genuine decline in semen quality over the past 50 years, and as male fertility is to some extent correlated with sperm count the results may reflect an overall reduction in male fertility.
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Are oestrogens involved in falling sperm counts and disorders of the male reproductive tract
TL;DR: It is argued that the increasing incidence of reproductive abnormalities in the human male may be related to increased oestrogen exposure in utero, and mechanisms by which this exposure could occur are identified.
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Decline in Semen Quality among Fertile Men in Paris during the Past 20 Years
TL;DR: The volume of seminal fluid, the sperm concentration, and the percentages of motile and morphologically normal spermatozoa in 1351 healthy fertile men from 1973 through 1992 were measured.
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Evidence of deteriorating semen quality in the United Kingdom: birth cohort study in 577 men in Scotland over 11 years
TL;DR: Data confirm previously published data from other countries that semen quality is changing, declining by about 2.1% per year Research is urgently required to examine the function as well as the number of sperm and to assess whether these changes are affecting human health and male fertility.
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Effect of Alcohol (Ethanol) Administration on Sex-Hormone Metabolism in Normal Men
TL;DR: It is shown that alcohol markedly affects testosterone metabolism independently of cirrhosis or nutritional factors and increased the metabolic clearance rate of testosterone in most subjects studied.