According to Dr. Shanna Swan, an environmental and reproductive epidemiologist at Mount Sinai Hospital in New York and the author of Count Down, sperm concentration in Western countries has been declining by approximately one percent each year. More than a fertility crisis, could this trend mean the threat of human extinction? And how can we combat it?

Men today have approximately half of the sperm their grandfathers had. And a woman in her 20s today is less fertile than her grandmother was at age 35. Beyond making it difficult to conceive a child, learn how the same issues that cause infertility can also impact our overall health and life duration.

For more information, check out The Global Fertility and Genetics: NYC Fertility Center’s website and Facebook. Dr. Swan’s book, which has 4.6 out of 5 stars with 361 ratings on Amazon.