The most babies are born in September and July, while November, December, and January have the fewest births worldwide.
An international team of scientists has published an online heat map that reveals the most popular months and days of the year for birthdays.
A heat map is a graphical tool that shows data using color, with individual values represented by different shades.
The most common birthdays worldwide are September 12, 18, 25, and 26—dates that fall nine months after the winter holidays. Those dates suggest colder months encourage people to spend more time indoors and, for many, to expand their families.
The data show very few births on major holidays, and there’s a noticeable drop in births on the 13th of each month. Scientists are still trying to fully explain these patterns, according to the Daily Mail.
The Best Month and Time for Conception
The team also identified an ideal time for couples trying to conceive: spring mornings around 7:30 a.m.
The researchers reached that conclusion after a large study at University Hospital Zurich in Switzerland. The study notes that sperm have a 24-hour circadian clock and show peak activity in the morning.
The researchers analyzed sperm samples from 7,068 men aged 25 to 40 who were undergoing infertility treatment. They measured sperm concentration, total count, progressive motility, and normal morphology. Sperm were most viable for fertilizing an egg in March, April, and May, when sperm counts were highest. The study found a significant decrease in concentration during the summer, Bridget Liners, the lead author, said.
