After years of studying the Baka people of Cameroon, Fernando Ramirez Rozzi was surprised to find a sudden drop in fertility (生育) among young women in 2011. He tried to remember what had happened in the community that could have caused the change. The biggest news was a bar opened in late 2010 in the village, selling a cheap, dangerous mix of methanol (甲醇) and ethanol (乙醇).
But was alcohol to blame for the decline in births? To answer that question, Ramirez Rozzi, a human paleontologist, compared the number of births before and after the bar opened. Ramirez Rozzi found the fertility rate dropped significantly after 2011 — from an average of 8. 8 babies per woman to 5. 6. And the rate decreased even more in younger women.
Alcohol — especially the dangerous mix sold at the new bar — has been shown to contribute to many serious health conditions, including infertility in women. Indeed, government authorities in Cameroon have banned the production of the kind because it causes major disorders of the nervous system, cancers, and death. That the drop in fertility was especially high among young women also pointed to alcohol, because they hung out at the bar more than older women, listening to loud music and getting drunk.
Ramirez Rozzi looked into other major changes, such as higher rates of disease. He found nothing. So he concludes that alcohol is to blame. Other researchers say Ramirez Rozzi's argument is convincing. "The case for alcohol abundance causing a drop in fertility is persuasive, says Nicholas Blurton-Jones, professor emeritus at the University of California, Los Angeles. Blurton-Jones was not involved with the new work, but he has studied another group of hunter-gatherers who also struggle with alcohol.
The drop in fertility could
threaten the Baka people's chances of survival over time 
Ramire Rozzi says. When he shared his data with the Baka women in a meeting last year, they told him they were very concerned about that.
