Worldwide Sperm Counts Are Dropping at an Alarming Rate
A new study shows sperm counts have dropped by 59% globally over the last 40 years.
There are 7.6 billion people on earth now, with that number expected to rise to 8.8 billion by 2050. That's according to the U.N.'s 2017 World Population Prospects Report. It's a lot of people — there were only about half of the current population in 1972 — but the U.N.'s prediction actually represents a slowing of the recent growth rate, from 1.24% to 1.1 %. That may not seem like much, but it is part of a downward trend, and a new report may shed some light on at least one reason: Over the last four decades, sperm counts worldwide have dropped by 59.3%, and they're apparently continuing to go down. This means there's an ever-growing number of men who are infertile or nearly so.
Sperm count is of concern to public health researchers for a few reasons. Most obviously, it's closely linked to male fecundity, and thus birth rates. Second, reduced sperm count has been linked to cryptorchidism, hypospadias and testicular cancer. Third, those little swimmers may be the canaries in the er, coal mine, since changes in their levels have been associated with environmental factors such as exposure to chemicals, pesticides, and heat, and with lifestyle factors such as stress, diet, smoking, and BMI.
Worries about semen quality go back at least as far as 1992, when a study was published that found, “There has been a genuine decline in semen quality over the past 50 years." The authors of the current research examined sperm concentrations (SC) and total sperm count (TSC) statistics listed in English-language studies dating back to January 1, 1981 — just after index of biomedical research MEDLINE added “sperm count" as a searchable term — and on up to December 31, 2013. They also worked with the Embase database.
The researchers were looking for studies of men who were either “unselected" — young males unlikely to even know if they were fertile or not — and “fertile" — men who'd already fathered children. The team excluded studies of men being treated for infertility or sub-fertility, men with genital abnormalities, diseases or certain medications, and those who'd been exposed in their jobs to extreme environmental influences. Also excluded were studies involving fewer than 10 subjects.
The huge percentage drop is largely a product of a 50-60% decline in sperm counts in North America, Europe, Australia, and New Zealand.
The SC and TSC declines add a physiological factor to a decline in birth rates that's been observed over the last two decades, often attributed to more women entering the work force than in the past.
While no one thinks the planet needs still more people to support, the drop in fertility suggested by this study raises two alarms for lead study author Hagai Levine, who's been left “very worried" by the findings, as he told the BBC:
• The low SC and TSC counts may represent assaults on our health in general from stressors in the environment: "If we will not change the ways that we are living and the environment and the chemicals that we are exposed to, I am very worried about what will happen in the future."
• Second, Levine says, “Eventually we may have a problem, and with reproduction in general, and it may be the extinction of the human species."
To create wiser adults, add empathy to the school curriculum.
- Stories are at the heart of learning, writes Cleary Vaughan-Lee, Executive Director for the Global Oneness Project. They have always challenged us to think beyond ourselves, expanding our experience and revealing deep truths.
- Vaughan-Lee explains 6 ways that storytelling can foster empathy and deliver powerful learning experiences.
- Global Oneness Project is a free library of stories—containing short documentaries, photo essays, and essays—that each contain a companion lesson plan and learning activities for students so they can expand their experience of the world.
This is what the world will look like, 250 million years from now
To us humans, the shape and location of oceans and continents seems fixed. But that's only because our lives are so short.
The future of education and work will rely on teaching students deeper problem-solving skills.
- Asking kids 'What do you want to be when you grow up?' is a question that used to make sense, says Jaime Casap. But it not longer does; the nature of automation and artificial intelligence means future jobs are likely to shift and reform many times over.
- Instead, educators should foster a culture of problem solving. Ask children: What problem do you want to solve? And what talents or passions do you have that can be the avenues by which you solve it?
- "[T]he future of education starts on Monday and then Tuesday and then Wednesday and it's constant and consistent and it's always growing, always improving, and if we create that culture I think that would bring us a long way," Casap says.
These Jurassic predators resorted to cannibalism when hit with hard times, according to a deliciously rare discovery.
- Rare fossil evidence of dinosaur cannibalism among the Allosaurus has been discovered.
- Scientists analyzed dinosaur bones found in the Mygatt-Moore Quarry in western Colorado, paying special attention to bite marks that were present on 2,368 of the bones.
- It's likely that the predatory carnivore only ate their already-dead peers during times when resources were scarce.
As a doctor, I am reminded every day of the fragility of the human body, how closely mortality lurks just around the corner.