You may have a hunch that a lot of your nearest and dearest are born during the summer months, and, as it turns out, you're onto something. According to a study from DailyViz, July, August, September, and October are the most popular birth months in the United States, with September ranking at number one. If you tie that to one of our favorite topics — yes, we're talking about birthday cake — that means there's bound to be many slices on your plate in the near future.