The problem isn't that something is inherently wrong with the human body as it has evolved over time; it's that chemicals in our environment and unhealthy lifestyle practices in our modern world are disrupting our hormonal balance, causing varying degrees of reproductive havoc that can foil fertility and lead to long-term health problems even after one has left the reproductive years. Similar effects are occurring among other species, adding up to widespread reproductive shock. Simply put, we're living in an age of reproductive reckoning that is having reverberating effects across the planet. (Page 2)

The most important events in a male's life, in terms of sexual and reproductive development, occur while he's still in utero. (Page 10)

And the changes in sexual development taking place all over the world appear to have been accompanied by an apparent rise in gender fluidity,' (Page 11)

The rate of adverse reproductive changes in males is increasing by about 1 percent per year. This includes the rates of declining sperm counts and testosterone levels, increasing rates of testicular cancer, and the projected worldwide increase in the prevalence of erectile dysfunction. On the female side of the equation, miscarriage rates are also increasing by about 1 percent per year. (Page 11)

Between 1973 and 2011, sperm concentration (the number of sperm per milliliter of semen) dropped more than 52 percent among random men in Western countries; meanwhile, the total sperm count fell by more than 59 percent. We came to these conclusions after examining the findings from 185 studies involving 42,935 men that had been conducted during this thirty-eight-year period. To be clear: these men weren't selected based on their fertility status; they were everyday Joes and Johns, ordinary men. (Page 13)

It's also shocking that in some parts of the world, the average twentysomething woman today is less fertile than her grandmother was at thirty-five. (Page 14)

While 69 percent of the aspiring sperm donors made the cut in 2003, only 44 percent did in 2013. This was true despite that the more recent group of guys had improved lifestyle variables such as a decline in alcohol use, smoking, and body weight and an increase in steady exercise. (Page 21)

Our idea of what's a "good enough" sperm concentration has actually gone down. It used to be 40 million/mL, then it was lowered by the WHO to 20 million/mL in 1980 and to 15 million/mL in 2010. For the sake of comparison, back in the 1940s, 60 million/mL was considered an adequate sperm count. (Page 26)

A hidden player in the men's infertility picture that often goes unrecognized: low testosterone. As previously mentioned, testosterone levels have been declining-by 1 percent per year since 1982, (Page 27)

Here's the surprising, counterintuitive fact of life: testosterone replacement therapy comes with its own downsides, including...wait for it...lowered sperm count! (Page 28)

Testosterone replacement therapy has been studied as a method of birth control because 90 percent of men can have their sperm counts drop to zero while they're on it. (Page 28)

As men age, particularly as they reach the north side of forty, their sperm is more susceptible to mutation, which can increase the risk that their children will be born with disorders such as autism and schizophrenia or Down syndrome. A man's age also can affect his female partner's miscarriage risk. Studies suggest that for men ages forty and older, their partner has a 60 percent increased risk of experiencing miscarriage, compared to fathers under thirty; the risk appears to be stronger for first-trimester pregnancy losses, which are more likely to be chromosomally abnormal. (Page 32)

From 1990 to 2011, the risk of miscarriage increased by 1 percent per year among pregnant women in the United States, according to a 2018 study by the Centers for Disease Control and Prevention. (Page 48)

One scientific theory suggests that in utero exposure to EDCS, particularly phthalates, which can lower a fetus's exposure to testosterone, may play a role; these chemicals have been associated with an increased risk of autism spectrum disorders (ASDS) in males. Interestingly, ASD and gender dysphoria, two seemingly unrelated conditions, occur together more often than expected. Another theory is that EDCS can interfere with complex biochemical pathways in the brain in ways affect how a person associates with his or her physiological sex at may that birth or expresses their gender through behavior, either of which may result in gender dysphoria. (Page 59)

When expectant mothers have a low exposure to an antiandrogenic phthalate called dibutyl phthalate (DBP) or they don't use Tylenol during pregnancy, the gender difference in language delay in their babies is large; by contrast, when pregnant women are exposed to high levels of DBP or Tylenol during pregnancy, there is little difference in language acquisition between boys and girls. Simply put, the language-development difference between the genders becomes blurred with these chemical exposures. I suspect many other qualities do, too. (Page 60)

Another aspect that has caused discomfort is the researcher's conclusion that other factors appear to play a contributing role in gender dysphoria, including a mental health condition, a sexualor gender-related trauma, a desire to escape one's emotions and difficult realities, a major family stress such as divorce or the death of a parent, or a high level of parent-child conflict. (Page 66)

Research has found an association between high prenatal exposures to EDCS-for instance, éxposures to pesticides or phthalates-and a higher risk of external genital malformations in male newborns. And researchers at the University if a parent had occupational of North Texas have explored the physiological pathways through which EDCS can influence sexual differentiation in humans. (Page 69)

In my studies we asked moms about how their four- to seven-year olds played, using a standard "play behavior" questionnaire, and we found that boys who were exposed in the womb to higher levels of the potent chemical di-2-ethylhexyl phthalate (DEHP), which can lower fetal testosterone levels, scored significantly lower on the "masculine scale"in other words, they were more likely to play with dolls and less likely to play with trucks and guns. Similarly, a 2014 study from the Netherlands used the same play-behavior questionnaire and found that exposure to dioxins and PCBS was associated with more feminine behavior in boys, whereas in girls, exposure to these chemicals was associated with less feminine play behavior. (Page 70)

The most sensitive time frame for reproductive tract development is the first trimester of pregnancy, when the genitals and the germ cells that will produce sperm are being formed-a phase called the reproductive programming window. (Page 75)

There's evidence that women's bodies spontaneously abort more male babies during stressful times. For example, the ratio of male to female live births declined in the three to five months after five different terrorist attacks around the world between 2001 and 2012. (Page 81)

The length of a baby's AGD can tell us what chemical influences the fetus was exposed to in the womb, as well as what the future holds for that person's reproductive health and fertility; thus, the AGD offers a rearview-mirror perspective and a forecast of the person's future health. (Page 85)

A grown man who smokes cigarettes typically experiences a 15 percent decline in his sperm count, an effect that can be reversed if he quits the habit; however, if an expectant mother smokes during pregnancy, her grown son may experience a fairly dramatic decrease in his sperm count-up to 40 percent-that is irreversible. It's not only chemicals that can have negative effects. New MƏ research suggests that if an expectant mother experiences significant life stress-such as job loss, divorce, or the death or illness of a loved one early in a pregnancy with a male fetus, her son is at increased risk for having reduced sperm count, fewer progressively motile sperm, and lower testosterone levels at age twenty. (Page 86)

During adolescence, for example, teens are particularly sensitive to the effects of alcohol and smoking, and research has revealed that early alcohol consumption (as early as sixth grade) can delay pubertal development. Developing breast tissue in girls is susceptible to the effects of certain phthalates, leading to increased breast density; pubertal gynecomastia, breast formation in boys, has also been linked with higher blood levels of certain phthalates. As far as below-the-belt effects go, sperm are being produced during puberty and are susceptible to the adverse effects of many factors, including chemicals that can alter the young man's hormones or the complicated physiological processes that work together to produce the sperm. (Page 88)

A 2015 study from Denmark found that regularly smoking marijuana more than once a week was associated with a 29 percent lower sperm count; even worse, men ages eighteen to twenty-eight who used marijuana more than once a week as well as other recreational drugs reduced their total sperm count by 55 percent. Among men undergoing fertility evaluation as a precursor to assisted reproduction, those who used large quantities of marijuana were four times more likely to have poor swimmers, and moderate users were nearly three and a half times more likely to have abnormally shaped sperm. (Page 96)

Some animal studies suggest that even cannabidiol (CBD), the second most prevalent active ingredient in marijuana, could damage sperm development and reduce the ability of sperm to fertilize an egg, (Page 97)

One of our studies found that when pregnant women ate seven or more beef-containing meals per week, their sons had reduced sperm counts. Meat processing-such as salting, curing, fermentation, and smoking-is also of concern. Men who eat a lot of processed meats (think hot dogs, bacon, sausage, salami, and bologna) tend to have a lower sperm count and a lower percentage of normally shaped sperm. (Page 99)

Tylenol has been shown to cause sperm abnormalities, including DNA fragmentation, and to increase the time it takes to achieve a pregnancy; moreover, taking high doses of Tylenol can alter the shape of sperm in ways that can compromise their fertilizing capabilities. (Page 104)

At every age, women are twice as likely to take antidepressants as men, and the use of these medications increased 64 percent from 1999 to 2014 for both genders. And-are you detecting a pattern?-the use of SSRIS (selective serotonin reuptake inhibitors), which are prescribed primarily for depression or anxiety, reduces sperm concentration and motility and increases the percentage of abnormal sperm. (Page 105)

These short-lived chemicals have half-lives of four to twenty-four hours. Even so, levels of human exposure to many nonpersistent chemicals-such as phthalates and phenols-tend to be fairly stable because of our continual use of products that contain them. (Page 110)

A large, diverse class of chemicals, phthalates are found in plastic and vinyl, floor and wall coverings, medical tubing and medical devices, and toys, as well as in a vast array of personal-care products (including nail polishes, perfumes, hair sprays, soaps, shampoos, and others). Phthalates are widely distributed throughout the body and can be measured in urine, blood, and breast milk. The most concerning phthalates are those that can decrease the production of male hormones such as testosterone (the antiandrogenic phthalates) that the male needs to become fully masculinized, changes that can make him more likely to be infertile or to simply have a lower sperm count. In this respect, the three particularly bad actors are di-2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DBP), and butyl benzyl phthalate (BBZP). Because of their reproductive toxicity, these three phthalates are scheduled to be gradually phased out in the European Union, along with others; that's not the case in the United States, though. (Page 115)

Since the 1970s, chemical flame retardants have been added to numerous materials to prevent or slow the growth of fire, in foam and upholstered furniture, mattresses, carpets, children's pajamas, computers, and other common products. There are dozens upon dozens of different flame retardants. While some have been removed from the market due to health or safety concerns, these gone-but-notforgotten chemicals don't break down easily; rather, they persist in the environment and can build up in fatty tissues in humans and animals. (Page 119)

When DDT also was found to be neurotoxic, it was replaced with organophosphate pesticides, another class that also has neurotoxic effects that interfere with a child's brain development. (Page 125)

Since bisphenol S was substituted for bisphenol A in many products touted as being "BPA-free," it has become apparent that these products also may interfere with endocrine function in ways that could promote premature puberty, obesity, and damage to a woman's eggs. I'm sure you get the picture. (Page 125)

In a 2016 study of some thirteen thousand men who'd been diagnosed with male factor infertility, researchers found that men with low sperm concentrations had a 30 percent increased risk of developing diabetes and a 48 percent increased risk of developing ischemic heart disease, compared to men without the infertility diagnosis. (Page 130)

Whether it's called "a sixth vital sign," a “harbinger," or “a fundamental biomarker," this much is clear: a man's semen quality can tell him something about his future health risks. On the upside, men with high-quality semen have a longer life expectancy and a decreased incidence of a wide range of diseases compared to their peers with infertility, according to a study of forty thousand Danish men (Page 130)

A recent study found that 88 percent of biopsies from bottlenose dolphins from the northern Adriatic Sea had PCB concentrations above the toxicity threshold for physiological effects in marine mammals, and 66 percent had concentrations above the threshold for reproductive impairment. (Page 145)

A shift in the sex ratio, which is usually in the direction of fewer male births, can be a sensitive indicator of sudden or pervasive environmental dangers. Surprisingly, a man's exposure to these dangers is more likely to lower the chances that his child will be a son than his female partner's exposure is. (Page 166)

Men who get more than seven hours week per of moderate to vigorous physical activity have 43 percent higher sperm concentrations than those who exercise an hour or less per week. (Page 177)

When researchers in China examined the effects of work stress on semen quality among 384 men, they found that men with high levels of work stress had a greater chance of having swimmers classified below the WHO's threshold for “normal" sperm concentration and total sperm count than those with low work stress.

No surprise there. Here's where things get interesting: the men who had  high work stress and high levels of social support had perfectly normal sperm. (Page 178)

Buy organic produce, whenever possible. (Page 182)

Avoid contaminants in animal products... the phrases raised without antibiotics, raised without added hormones, or no synthetic hormones mean the animal received no antibiotics or hormones during its lifetime. (Page 183)

For food storage, your best bet is to use glass, metal, or ceramic containers with tops or aluminum foil. If you do opt for plastic containers, use this rhyme to help you remember which recycling codes are safer and which aren't: 4, 5, 1, and 2, all the rest are bad for you. (Page 184)

Upgrade your cookware. If you've been using nonstick pots and pans, it's time for a change: Nonstick cookware is made with PFOA (perfluorooctanoic acid) compounds or Teflon (a brand name for the chemical polytetrafluoroethylene). (Page 185)

Filter your drinking water. Even if you like the taste of your tap water and trust your water supplier, it's a good idea to buy a water filter for your home (or fridge), and remember to change it regularly. (Page 185)

Clean up your cleaning products. Carpet shampoo, all-purpose household cleaners, window- and wood-cleaning products, disinfectants, stain removers, and most other cleaning products contain potent toxins and EDCS. (Page 185)

Similarly, paraben-free and phthalate-free indicate that these chemicals aren't in the product. Avoid cleansers and skin-care products that are labeled antibacterial; regular soap and water are all you need to get clean. (Page 187)

In particular, avoid products that contain the following EDCS or other harmful chemicals: triclosan (often in liquid soap and toothpaste), dibutyl phthalate or DBP (in hair spray and nail products), and parabens such as methyl-, ethyl-, propyl-, isopropyl-, butyl- and isobutylparaben (preservatives found in shampoos, conditioners, facial and skin cleansers, moisturizers, deodorants, sunscreens, toothpastes, and makeup). To closely vet the personal-care products you like, check out the Environmental Working Group's "Skin Deep" database for details. (Page 188)

Remove wall-to-wall carpet. Synthetic carpets, such as those made from nylon or polypropylene, can emit harmful chemicals into the air (another example of off-gassing) for many years. (Page 189)

Upgrade your replacement purchases. If you're in the market for a new stereo or media system, choose electronics without PBDES or other brominated flame retardants. If you're ready to buy a new couch, comfy chair, or mattress, choose those that are free of flame-retardant chemicals, toxic adhesives (such as those containing formaldehyde), or plastics. (Page 190)

The Silent Spring Institute offers a free smartphone app called Detox Me, which provides simple, evidence-based tips on how to reduce exposure to these chemicals in your home, and a Detox Me Action Kit, a urine test that allows you to detect the presence of common household toxins in your body. (Page 193)

More than a decade later, in 1911, experiments on rats raised “reasonable grounds" for suspicion that exposure to asbestos dust is harmful to the health of living creatures. Between 1935 and 1949, an alarming number of lung cancer cases were reported among asbestos-manufacturing workers, and in 1955 research established a high risk for lung cancer among asbestos workers in Rochdale, in the UK. Between 1959 and 1964, mesothelioma cancer, which affects the tissue lining the lungs, was found to be a significant problem in asbestos-manufacturing workers and people living in neighborhoods near factories that handled asbestos in South Africa, the UK, and the United States. Nevertheless, it took until 1973 for all forms of asbestos to be recognized as carcinogenic to humans and until 1999 for many countries in Western Europe to ban the use of all types of asbestos. That's an entire century! (Page 196)