During the last decades, infertility and reproductive abnormalities have evolved to major issues globally. Hundreds of couples worldwide have faced serious difficulties in conceiving naturally due to a number of fertility problems affecting both sexes. It is well known that the percentage of couples conceiving through IVF (in vitro fertilization) is steadily rising. In fact, according to estimates, 5 million babies have been born using IVF since the world’s first in 1978.
Regarding the male reproductive health, there are several studies which have shown a global decrease in semen production. For example, a study published in 2013 showed that sperm production exhibited a decrease of nearly 2% per year from 1996 to 2005, in a sample of 26,000 French men¹. It goes without saying that the latter finding demonstrates the size of the problem.
The doctor’s hypothesis is that fertility problems are related to environmental factors and in particular, to people’s exposure to “endocrine-disrupting chemicals”. These, man-made, chemicals have the ability to modulate the action of human hormones. They also disrupt the good function of the natural hormones of the human organism by interfering to the endocrine system, that’s why they are called endocrine disrupters.
Bisphenol- A (BPA) is a chemical of this kind which, in fact, mimics the effects of estrogen. Numerous studies have reported the disrupting effect of estrogenic exposures. A new study though proves that exposure to BPA, an endocrine disruptor find in many plastics, receipts and food cans, might be responsible for this tremendous decline in male fertility.
The scientists involved in the study used different types of mice in their experiments. At first, they exposed the newborn mice to BPA and when the mice were sexually mature they examined their testes and counted their sperm production. The semen count was remarkably lower in exposed males. Continuing with the experiments, the scientists transplanted the spermatological stem cells from exposed mice into healthy, namely unexposed, mice. The result was quite shocking, as the sperm production was also remarkably low. The scientists concluded that the early-life exposure to BPA results in the permanent disruption of the cells producing the semen.
Patricia Hunt, the lead scientist of the study and a geneticist at Washington State University, said that exposure to estrogens “is not simply affecting sperm being produced now, but impacting the stem cell population, and that will affect sperm produced throughout the lifetime”².
Furthermore, the researchers exposed mice to other chemical endocrine disruptors and in particular to ethinyl estradiol, which is found in oral contraceptive pills. The results demonstrated that BPA as well as ethinyl estradiol alter the way that germ cells carry out the DNA’s copying and splicing process by affecting the cells’ process of producing sperm in the testes. It should be stressed here that the latter is a cells’ process called meiosis and is similar to all mammals, consequently to humans as well.
- Original article