WHAT CAUSES DECLINING SPERM?
NEW YORK TIMES writer Gina Kolata this week renewed her efforts
to discredit the theory and evidence that industrial chemicals
interfere with hormones, causing harm to wildlife and humans.
A month ago, Ms. Kolata savagely attacked the new book, OUR
STOLEN FUTURE, claiming that "careful studies" (none of which
she cited) had "refuted" the premise of the book. (See REHW
#486.) OUR STOLEN FUTURE reviewed hundreds of studies published
in peer-reviewed journals. The book offers substantial evidence
that industrial pollutants may be interfering with the hormones
that regulate growth, health and behavior in wildlife and humans,
thus contributing to birth defects, problems of sexual
development, breast cancer, prostate cancer, and even mental
problems like attention deficit disorder, diminished IQ, and
Among the evidence discussed in OUR STOLEN FUTURE was declining
sperm counts in men in industrialized countries, plus data and
hypotheses linking such a decline to hormone-disrupting
chemicals. In 1992, a report in the BRITISH MEDICAL JOURNAL
analyzed 61 previous sperm studies conducted in 20 countries,
concluding that average sperm counts had declined from 113
million sperm per milliliter of semen to 66 million during the
past 50 years, a 42% decline.
Ms. Kolata has made this her special cause, evidently determined
to convince TIMES readers that there's nothing to it. On the
same day that she maligned OUR STOLEN FUTURE (March 19th), Ms.
Kolata published a second article in the TIMES, about sperm
counts. It is clear from Ms. Kolata's March 19th article that
she requires little or no evidence to be persuaded that sperm
counts are not declining. Instead of evidence, she offers two
(1) From 1960 to 1970 a million women were exposed to a synthetic
sex hormone called DES. Recently, a large study of male
offspring of DES-exposed mothers showed that these men are
fertile, able to father children. Ms. Kolata apparently wants
her readers to believe that this means DES did not cause a
decline in sperm counts among these men.
(2) Ms. Kolata offers her readers the opinion that infertility is
not increasing in the U.S.
The important point is that these arguments are both straw men.
Neither argument reveals anything important about sperm counts.
The original analysis of 61 studies of sperm counts showed a
decline from 113 million sperm per milliliter (ml) of semen in
1940 to an average of 66 million in 1990. Men are able to sire
children with a sperm count as low as 20 million sperm per ml,
and they are not definitely sterile until their sperm count drops
to 5 million. No one has ever claimed that average sperm counts
world-wide have dropped this low. Ms. Kolata has set up a straw
man and triumphantly demolished it, but in the process has misled
her readers about the question of declining sperm counts. (In
fact a decline in sperm quality and quantity has been reported
among the sons of DES-exposed women, along with underdeveloped
and undescended testicles and stunted penises. These men were
not sterilized but the sperm of many of them was definitely
diminished by their mother's exposure to DES.)
This week Ms. Kolata took up the sperm count cause again in the
TIMES. On April 29, she reviewed three recent studies of
sperm, omitting mention of other recent studies that don't
support her bias. She highlighted two new studies that indicate
sperm counts have slightly INCREASED over the past 25 years among
students in Seattle, and among men preparing to have
vasectomies in Los Angeles, New York, and Roseville,
Minnesota. Ms. Kolata describes a third study, by Harry
Fisch, which re-analyzes the 61 previous studies.
Ms. Kolata gives great weight to Dr. Fisch's re-analysis of the
61 studies, which concludes that sperm counts may not be
declining worldwide. Dr. Fisch argues that the "decline" in
sperm counts is really just previously-unnoticed "geographic
variation" in sperm counts. In other words, Dr. Fisch argues
that sperm counts may not actually be declining; instead, they
may be holding steady, but they may APPEAR to be declining
because there is so much variation between sperm counts in
Ms. Kolata failed to mention it, but to reach his new conclusions
about worldwide sperm counts, Dr. Fisch threw out 41 of the 61
original studies, re-analyzing only 20 of the original 61. He
says he did this because the study populations in those 41
studies were small, involving all together only 9% of the
original total study population. However, in so doing, Dr. Fisch
reduced the number of countries involved from 20 to only 12. On
the basis of the much smaller number of studies, from the much
smaller number of countries, he concluded that sperm counts have
not declined. Exclusion of so many relevant studies seems
dubious at best.
Ms. Kolata explains Dr. Fisch's findings this way: "Dr. Fisch
argues that the decline reported was probably a result of
previously unappreciated regional variations in sperm counts.
Most of the early studies, with the high sperm counts, involved
New York men, whose sperm counts have remained among the highest
in the world. Most of the more recent studies involved men from
developing countries and their sperm counts, for unknown reasons,
tend to be lower." But is this true? Is Paris in a developing
country? Is London? Is Brussels? Is Scotland a
developing country? These are all places where good recent
studies have reported declining sperm counts.
Ms. Kolata chose not to tell her TIMES readers about these
important recent studies.
One new study reveals that sperm quantity has not changed for 20
years in rural Toulouse, France. The authors of the Toulouse
study suggest that environmental factors might distinguish
Toulouse from Paris, where sperm counts seem to be declining.
Combined with the two new U.S. studies, does the Toulouse study
mean that all the other recent studies showing declines are wrong?
The U.S. studies do not seem particularly persuasive. Students
in Seattle are unlikely to be representative of the general
populace. Neither, necessarily, are a self-selected population of
men preparing to have vasectomies. A general decline in sperm
counts could be occurring, yet might not be revealed by studies
of these particular populations.
Based on the Toulouse study, we can say that it is good news that
some populations can be found who may not be experiencing
declines in sperm. But it is not news that some populations have
high sperm counts and others have low. The original analysis of
61 studies in 1992 made this very clear. No matter what is
happening to the worldwide average, the question therefore
remains: why is sperm count in some large populations low and/or
declining? Gina Kolata seems to want her readers to believe
that declines are not occurring and that low counts occur only in
developing countries. But in his analysis Harry Fisch
acknowledges the problem, and answers it this way: the
"geographic variations" in sperm might be caused by environmental
factors, nutrition, socioeconomic differences, or some other
"unknown causes," he says.
In other words, it is entirely possible that "environmental
factors," such as hormone-disrupting chemicals, are affecting
some large populations, causing a decline in sperm. Back in
1983, U.S. EPA [Environmental Protection Agency] identified 52
chemicals or groups of chemicals that adversely affected sperm
(as well as 11 that enhanced sperm). We have already seen
that DES had adverse effects on the sperm of sons of DES-treated
women. Is there laboratory data supporting such an idea?
Elaborate new studies of mice, reported in ENVIRONMENTAL HEALTH
PERSPECTIVES (a U.S. government publication) in December, reveal
that exposing pregnant mice to low levels of an estrogenic
chemical causes their male offspring to develop
smaller-than-normal testicles, and to produce less sperm than
untreated mice. Three separate industrial chemicals (with
estrogenic properties) were tested and they all caused small
testicles and diminished sperm counts. (DES was also tested, as a
"positive control," and --no surprise --it had the same effect.)
The estrogenic chemicals used in these experiments are industrial
pollutants commonly found in our food and water.
Gina Kolata chose not to tell her TIMES readers about these
important new animal studies.
 Gina Kolata, "Are U.S. Men Less Fertile? Latest Research Says
No," NEW YORK TIMES April 29, 1996, pg. A14
 Theo Colborn, Dianne Dumanoski, and John Peterson Myers, OUR
STOLEN FUTURE (N.Y.: Dutton, 1996).
 Elisabeth Carlsen and others, "Evidence for decreasing
quality of semen during past 50 years," BRITISH MEDICAL JOURNAL
Vol. 305 (1992), pgs. 609-613. We have previously reported on
this study, and subsequent studies. See REHW #290, #343, #369,
#390, #436, #438, #446, #447, #448, #457.
 Gina Kolata, "Sperm Counts: Some Experts See a Fall, Others
Poor Data," NEW YORK TIMES March 19, 1996, pg. C10.
 Allen J. Wilcox and others, "Fertility in Men Exposed
Prenatally to Diethylstilbestrol," NEW ENGLAND JOURNAL OF
MEDICINE Vol. 332, No. 21 (May 25, 1995), pgs. 1411-1416.
 There is some evidence that this is untrue. Congress's
Office of Technology Assessment (OTA) reported several years ago
that Americans in their prime reproductive years (ages 20 to 24)
have experienced an increase in infertility in recent years. See
"Reproductive Dysfunction in the Population," in U.S. Congress,
Office of Technology Assessment, REPRODUCTIVE HEALTH HAZARDS IN
THE WORKPLACE [OTA-BA-266] (Washington, DC: U.S. Government
Printing Office, 1985), pgs. 341-364.
 The evidence is reviewed in Leon Earl Gray, Jr.,
"Chemical-Induced Alterations of Sexual Differentiation: A Review
of Effects in Humans and Rodents," in Theo Colborn and Coralie
Clement, editors, CHEMICALLY-INDUCED ALTERATIONS IN SEXUAL AND
FUNCTIONAL DEVELOPMENT: THE WILDLIFE/HUMAN CONNECTION (Princeton,
N.J.: Princeton Scientific Publishing Co., 1992), pgs. 203-230.
And see J.A. McLachlan, "Rodent Models for Perinatal Exposure to
Diethylstilbestrol and Their Relation to Human Disease in the
Male," in A.L. Herbst and H.A. Bern, editors, DEVELOPMENTAL
EFFECTS OF DIETHYLSTILBESTROL IN PREGNANCY (New York:
Thieme-Stratton, Inc., 1981), pgs. 48-157. And see: W. Gill,
"Effects on Human Males of IN-UTERO Exposure to Exogenous Sex
Hormones," in T. Mori and H. Nagasawa, editors, TOXICITY OF
HORMONES IN PERINATAL LIFE (Boca Raton, Florida: CRC Press,
1988), pgs. 162-174.
 C. Alvin Paulsen and others, "Data from men in Greater
Seattle area reveals no downward trend in semen quality: further
evidence that deterioration of semen quality is not
geographically uniform," FERTILITY AND STERILITY Vol. 65, No. 5
(May, 1966), pgs. 1015-1020.
 Harry Fisch and others, "Semen Analyses in 1,283 men from the
United States over a 25-year period: no decline in quality,"
FERTILITY AND STERILITY Vol. 65, No. 5 (May, 1996), pgs.
 Harry Fisch and Erik T. Goluboff, "Geographic variations in
sperm counts: a potential cause of bias in studies of semen
quality," FERTILITY AND STERILITY Vol. 65, No. 5 (May, 1996),
 Jacques Auger and others, "Decline in Semen Quality Among
Fertile Men in Paris During the Past 20 years," NEW ENGLAND
JOURNAL OF MEDICINE Vol. 332, No. 5 (February 2, 1995), pgs.
 D. Stewart Irvine, "Falling sperm quality," BRITISH MEDICAL
JOURNAL Vol. 309 (August 13, 1994), pg. 476.
 K. Van Waeleghem and others, "Deterioration of sperm quality
in young Belgian men during recent decades," HUMAN REPRODUCTION
Vol. 9, Supplement 4 (1994), pg. 73.
 Stewart Irvine and others, "Evidence of deteriorating semen
quality in the United Kingdom: birth cohort study in 577 men in
Scotland over 11 years," BRITISH MEDICAL JOURNAL Vol. 312
(February 24, 1996), pgs. 467-471.
 L. Bujan and others, "Time series analysis of sperm
concentration in fertile men in Toulouse, France between 1977 and
1992," BRITISH MEDICAL JOURNAL Vol. 312 (February 24, 1996), pgs.
 Andrew J. Wyrobek and others, "An evaluation of human sperm
as indicators of chemically induced alterations of spermatogenic
function," MUTATION RESEARCH Vol. 115 (1983), pgs. 73-148.
 Richard M. Sharpe and others, "Gestational and Lactational
Exposure of Rats to Xenoestrogens Results in Reduced Testicular
Size and Sperm Production," ENVIRONMENTAL HEALTH PERSPECTIVES
Vol. 103, No. 12 (December, 1995), pgs. 1136-1143. The chemicals
tested were 4-octylphenol (OP), butyl benzyl phthalate (BBP), and
octylphenol polyethoxylate (OPP). BPP is a phthalate, many of
which are common in the environment and in our food because they
are widely used as plasticizers.
Descriptor terms: sperm count; hormones; hormone disrupters; new
york times; gina kolata; our stolen future; des; infertility;
4-octylphenol; butyl benzyl phthalate; octylphenol
polyethoxylate; los angeles; new york; seattle; studies;
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