Decline in semen quality among fertile men in Paris during the past 20 years

Article Abstract:

A decline in sperm concentration and motility appears to have taken place in men between the years 1973 and 1992. Sperm concentration is the amount of sperm found in a given amount of semen and sperm motility refers to the ability of the sperm to move in an effective manner. Semen samples from 1,351 healthy fertile men collected at a single sperm bank in Paris from 1973 to 1992 were studied. The mean volume of seminal fluid remained constant throughout the years studied. Mean sperm concentration, on the other hand, decreased 2.1% per year. Part of this decrease is attributable to the mean age of the men increasing, but this does not account for the overall decrease in mean sperm concentration. Nor does it account for the 0.6% decrease yearly in the percentage of motile sperm or the 0.5% annual decrease in the percentage of normal spermatozoa.

Evaluation, Spermatozoa, Sperm motility

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Brief report: Intragenic deletion of the KALIG-1 gene in Kallmann's syndrome

Article Abstract:

One form of Kallmann's syndrome may involve a mutation in a gene on the X-chromosome that controls the development of cells in the hypothalamus that secrete gonadotropin-releasing hormone (GnRH). Kallmann's syndrome is caused by a deficiency of this hormone, which in turn causes incomplete sexual development. Of 77 families with Kallmann's syndrome, one was found to have a mutation of the KALIG-1 gene associated with Kallmann's syndrome. Two brothers had the mutation, as did their mother, although she did not have the syndrome. Both sons had incompletely developed testes and penis and no sense of smell. The DNA sequence of KALIG-1 indicates that it produces a protein involved in the migration of nerve cells that secrete GnRH from the olfactory region of the brain (responsible for the sense of smell) to the hypothalamus.

Health aspects, Causes of, Genetic disorders, Chromosome abnormalities

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Are semen quality and male fertility changing?

Article Abstract:

It remains to be proven whether or not male fertility and semen quality are declining, despite studies that suggest as much. Such studies do not use representative samples of men and fail to account for the variations in the sperm count and motility of a single man's semen over time. The regression analyses used in many of these studies do not account for all changes in sample size and other factors over time, making them somewhat suspect. Furthermore, rates of fertility among men have been steady since the 1960s, based upon the number of men seeking treatment for infertility. Even if sperm concentration is declining, more advanced measures of sperm fertility suggest that sperm concentration may a play a small role in male fertility.

Editorial, Research, Analysis, Infertility, Male, Male infertility

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