It’s common knowledge that today, we live longer than generations before us because of advanced medicine and better living conditions. Scientists have even speculated that the first person to live to 1,000 is already alive.

But while many of us watch our diets and regularly exercise to work on our longevity, the key to living longer may be much simpler: Just have a fall birthday. That’s right—if you’re born in September, October, or November, you may have above-average chances of living an extra-long life. Researchers from the University of Chicago compiled data on more than 1,500 people born between 1880 and 1895 who lived to be 100 or older, and compared their backgrounds with those of nearly 12,000 of their siblings and spouses. (This way, they could observe the effect of month-of-birth on life span instead of living conditions.) Published in the Journal of Aging Research, the study also found March, May, and July produced 40 percent fewer centenarians than other months.

One theory? Milder weather places less stress on babies and causes fewer seasonal infections. Also, pregnant mothers at the turn of the century might have had access to different nutrients depending on the seasons. But don’t despair (or rejoice) if your birthday falls during those months: Who knows what science will develop in your lifetime to help you get to the big 1-0-0?