11.4 Reproduction (HL)

Assessing risks and benefits associated with scientific research—the risks to human male fertility were not adequately assessed before steroids related to progesterone and estrogen were released into the environment as a result of the use of the female contraceptive pill.

There are a lot of myths surrounding the environmental effects of the contraceptive pill, despite the fact that it is one of the most widely-taken and best studied drugs in use. According to the ARHP, more than 13 million American women use the pill and there is over 50 years of data on its safety and effectiveness (Moore et al.).

Concerns have been raised that the additional estrogen, largely a synthetic estrogen called Ethinyl Estradiol, being released into the environment through usage of the pill has resulted in elevated rates of these hormones in drinking water.  As steroid hormones, these are known as Endocrine Disruptive Chemicals (EDCs) – chemicals that could alter the hormonal balance and control of organism’ physiology (Moore et. al.) Clearly then, there are legitimate concerns for the health impacts of any chemical that can disrupt an animal (or person’s) endocrine system.  The increase in male infertility as well as the recorded feminisation of some species of fish over this time period has amplified this issue. But is the contraceptive pill a significant part of this problem?

A comprehensive review (Wise et al.) examined this statement and found that the contraceptive pill is a negligible cause of any synthetic estrogens in waterways. It does highlight the role of agriculture and industry as sources of EDCs; for example, it points out that the amount of synthetic estrogen given to livestock in the US is five times greater than that consumed by all the women on the pill (Wise et. al.)

Screen Shot 2016-03-30 at 2.20.24 PM
Sources of endocrine-disrupting compounds in the water supply (Moore et al.)

Returning to the statement in the Nature of Science, there remains the issue of whether the risks were properly considered before the widespread use of these drugs and thus whether a full ethical review was conducted.  However, the link between estrogen compounds in the environment and the pill seem tenuous at best and it is other sources of steroid-based hormones that need to be addressed.

Sources:

Moore, K. et al. Birth Control Hormones In Water: Separating Myth From Fact. arhp.org. 2011. Web. Mar 30, 2016.

Wise A, O’Brien K, Woodruff T. Critical review: are oral contraceptives a significant contributor to the estrogenicity of drinking water?. Environ Sci Tech. 2011;1:51–60

Advertisements

6.6 Hormones, Homeostasis and Reproduction

Developments in scientific research follow improvements in apparatus—William Harvey was hampered in his observational research into reproduction by lack of equipment. The microscope was invented 17 years after his death.

Harvey
Harvey’s 1651 Publication. (Anatomia Animata)

We encountered Harvey in the NOS for Topic 6.2 on Circulation. In addition to his studies of the circulatory system, Harvey was responsible for a key publication on reproduction -the 75 chapter opus Exercitationes de Generatione Animalium (Experiments in Animal Generation),  published in 1651. This was an important publication, as Harvey made many key observations and overturned existing ideas on reproduction. Some of the highlights include:

  • landmark drawings and observations of the stages of embryonic development in chickens
  • denouncing the theory of spontaneous generation by discussing how maggots emerge from eggs
  • providing evidence, through comparative anatomy and observations, that argued against the idea of preformation – that the sperm or egg contains an already perfectly formed tiny animal (like a series of Russian dolls)
  • overturning the Aristotelian theory that conception resulted from the fusion of menstrual blood with semen.

In addition, his work on the dissection of female deer reproductive systems at different stages of pregnancy provided a new insight into this previously misunderstood aspect of physiology. However, he was limited in what he could observe here.  He was unable to find eggs or embryos until about six or seven weeks into the pregnancy, hampered by a lack of technology that could magnify the tissue. Thus his theory that epigenesis, rather than preformation, was the correct path for development could not be confirmed until the microscope was invented.

 

Sources:

“Anatomia Animata: Generation And Reproduction”. Indiana.edu. N. p., 2009. Web. 16 Mar. 2016.

“Embryology – History Of Embryology As A Science”. Science.jrank.org. N. p., 2016. Web. 16 Mar. 2016.

Lopez, Angel, “William Harvey (1578-1657)”. Embryo Project Encyclopedia. Arizona State University. 2010. Web. Mar 16, 2016.