Blog dedicated primarily to randomly selected news items; comments reflecting personal perceptions

Sunday, March 26, 2017

Endocrine Disrupters : Falling Birth Rate

"Your odds of getting into Harvard or Stanford are higher than your chances of being accepted as a donor at the major sperm banks."
"The bar is lower for members of ethnic groups that tend to be shorter. And given a perpetual lack of African-American donors, height may not be a disqualifier for black donors."
Tamar Lewin, The New York Times

"[Scientists report an increasing proportion of sperm] are misshapen, sometimes with two heads or two tails."
"Even when properly shaped, today's sperm are often pathetic swimmers, veering like drunks or paddling crazily in circles. Sperm counts also appear to have dropped sharply in the last 75 years, in ways that affect our ability to reproduce."
Nicholas Kristof, The New York Times

"Semen quality and fertility in men have decreased. Not everyone who wants to reproduce will be able to. The costs of male disorders to quality of life, and the economic burden to society, are inestimable."
Dr Andrea Gore, professor of pharmacology, University of Texas at Austin, editor of the journal Endocrinology

A sperm under the influence of an endocrine disrupting chemical in sunscreen. Because of chemicals like these, sperm have trouble swimming properly to deliver the goods. Credit Prof. Timo Strünker, Münster, Germany
"I think we are at a turning point.  It is a matter of whether we can sustain ourselves", stated Dr Niels Erik Skakkebaek, a Danish fertility scholar and pioneer in the field. This failure of the human body to continue to produce viable sperm in convincing numbers to ensure that the biological imperative to reproduce, thus sustaining the species remains intact, appears to be a scientifically universally-recognized global phenomenon of frightening proportions.

In Hunan province, China, where in 2001, 56 percent of sperm-donor applicants met health standards, that number descended precipitously to 18 percent by 2015. This was a large study, involving over 30,000 men. The findings led to the obvious conclusion that "The semen quality among young Chinese men has declined over a period of fifteen years."

What an irony; couples who are turning increasingly to medical interventions when they find themselves unable to procreate, look for help with sperm or eggs healthier than their own as they launch themselves into a long, frustrating and very often failing effort to achieve parenthood through assisted reproduction technology. Yet they have become dependent on sperm increasingly more difficult to harvest because failing sperm health is afflicting availability of suitable alternatives at sperm banks.

Sperm banks are increasingly finding it difficult to accept sperm from donors when the men  being recruited are seen to increasingly have low sperm count and sperm whose condition is far less than optimal in condition. The growing relative rarity of healthy sperm has driven the price of a sperm vial up astronomically. Sperm banks look for a good personal health history in recruits. A sparsity of sperm, those of poor quality, and white males of short stature tend not to qualify.

Scientific studies have indicated that a chemical type known as endocrine disrupters are likely responsible for the sub-par quality of sperm in male populations. If it were any other kind of chemical the warning could be circulated that the chemical is to be avoided by all means. But if that chemical is one used in many of the most common products utilized by society today, it becomes difficult to distance oneself from it.

These are the chemicals in plastics, in pesticides, in cosmetics and other products whose safety is taken for granted, and which manufacturers regard as indispensable to the manufacture of their frequently- and commonly-used products. A seven-year experiment was conducted on an Ontario lake by Canadian scientists who added endocrine disrupting chemicals to the water to observe the impact on fathead minnows. Males were turned into intersex fish, incapable of reproducing.

Denmark, along with South Korea, Spain, Germany and Italy are sufficiently concerned with sustainable reproduction, as to look elsewhere for additional answers to the cause of the dilemma, not entirely convinced that quantity and quality of spermatozoa is responsible for the notably lower success in achieving pregnancies.

There has been a increase in testicular cancer among young men. There is the biological problem of undescended testicles, as well as a congenital malformation of the penis, called hypospadias. Both, of course, could also be derived from the prevalence in the products we use of bio-disruptive chemicals.
Additives known as endocrine disrupting chemicals (EDCs) compromise male fertility by interfering with a membrane-bound calcium channel that normally controls motility of sperm cells, according to researchers in Germany and Denmark. EDCs are used in hundreds of household products—including toothpastes, sunscreens, cosmetics, plastic bottles, and toys—and scientists determined that they can cause fertility problems in previous studies. But a study published in the journal EMBO reports yesterday (May 12) is the first to posit a mechanism for how the chemical additives affect fertility in the human reproductive tract.
The Scientist, May 2014

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