Are Industrial Chemicals Causing Shrinking Penis Size? Scientist Thinks So

Reproductive epidemiologist Shanna Swan has written a new book that lays out the results of her scientific studies in ways people might actually pay attention to: Common industrial chemicals, she says, are shrinking penis sizes in men; decreased libido in women; falling fertility rates; and more, Pink News reports.

The book, titled "Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperilling the Future of the Human Race," shows how "phathalates, a chemical used in manufacturing plastics... impacts the hormone-producing endocrine system," Pink News summarizes.

"Because of this pollution, Dr. Swan says, fertility rates are rapidly falling – and a growing number of babies are being born with smaller penises."

Covering the story, UK newspaper the Guardian noted that the chemicals Swan warns about "are found in everything from plastic containers and food wrapping, to waterproof clothes and fragrances in cleaning products, to soaps and shampoos, to electronics and carpeting."

In addition to such "reproductive havoc," The Intercept reports, Swan has linked phathates to "higher rates of erectile dysfunction," as well as "eroding sex differences in some animal species; and potentially even [effects on] behaviors that are thought of as gender-typical," such as how children play and their language acquisition.

"Sexually dimorphic play is controversial," Swan noted in her interview with The Intercept. "Some people say it's all socially determined. And it undoubtedly does have social determinants, but it also has physiological determinants. And we showed that in two studies."

Still, Swan cautioned, it's too early to make definitive statements about how chemicals now known to affect sexual health and fertility in adults affect the development of children.

However, she went on to note, the effects of the chemicals are cumulative across generations. "If you're pregnant, and you're carrying a boy, the chemicals you're exposed to can pass to him through the placenta," she explained. "So the germ cells that will create his children are already affected."

Factor in a person's additional exposure to chemicals across a lifetime, and, she said, any given individual is vulnerable to a "two-hit model."

"Or, for subsequent generations, a three-hit or four-hit model," Swan added, saying that this is an explanation for "this continuing decline in fertility and sperm quality" that scientists are noting over time.