Sep 9, 2026 04:39 PM
https://www.popsci.com/science/why-septe...-birthday/
EXCERPTS: In 2016, statistics organization FiveThirtyEight and data journalist Matt Styles analyzed data on the average number of births per year from 1994 to 2014. In that 10-year-period, September tops the with nine out of the 10 most common birthdays falling on September. Based on this analysis, the ninth day of the ninth month is the most popular birthday.
The reasons behind this surge of September babies are likely couples spending more time indoors during the colder months of the year and holiday season. Some people tend to work less as the holidays approach, so there is more time to party-hop, drink a few more cocktails than usual, and the rest is clear. Pregnancies are supposed to last 38 weeks from conception, so babies born on September 9 would have likely been conceived on December 17.
[...] Some other hypotheses behind this surge in cold weather conceptions are that the shorter days may affect hormones and that sperm may be less potent in the warmer summer months... (MORE - missing details)
EXCERPTS: In 2016, statistics organization FiveThirtyEight and data journalist Matt Styles analyzed data on the average number of births per year from 1994 to 2014. In that 10-year-period, September tops the with nine out of the 10 most common birthdays falling on September. Based on this analysis, the ninth day of the ninth month is the most popular birthday.
The reasons behind this surge of September babies are likely couples spending more time indoors during the colder months of the year and holiday season. Some people tend to work less as the holidays approach, so there is more time to party-hop, drink a few more cocktails than usual, and the rest is clear. Pregnancies are supposed to last 38 weeks from conception, so babies born on September 9 would have likely been conceived on December 17.
[...] Some other hypotheses behind this surge in cold weather conceptions are that the shorter days may affect hormones and that sperm may be less potent in the warmer summer months... (MORE - missing details)