Baby dog teeth have roots, which should be absorbed as the adult teeth come in. However, this does not always happen. If the root does not absorb, or the absorption is slowed, the puppy tooth does not allow the dog tooth to come in.
Using Harvard University data, the graph shows September 16 as the most common birthday in the U.S., while December 25 and February 29 are the least common. The heat graph, while telling you how popular your birthday is, also successfully tracks trends in the data. Evidently, a large proportion of babies are born in September, with the top ten birthdays falling within the autumn month. Possibly confirming suspicions we have long held about conception trends, September is nine months after the holiday season.
August had the most births each year from 1990 to 2006 except for six years (1992, 1993, 1997, 1998, 2003 and 2004) when it was edged out by July, according to National Center for Health Statistics. Historically, the sweltering, late-summer months are when obstetricians witness an increase in the arrival of newborns.