In the last generation, male fertility has been declining in developed countries, with sperm density dropping 1.5% drop per year in the U.S. and 3% in Europe and Australia. Add to that the later marriage age in the West, along with more women delaying childbirth, and you have a growing number of couples with fertility issues.

Science News reports that the most common male genital birth defect is undescended testicles, which affects about three in every 100 American boys. No surprise there. But here's the new news: A mom's alcohol consumption during pregnancy appears to triple the risk that a woman's son will have undescended testicles.