As we know, we, unfortunately, cannot choose our birthday. Otherwise, it would be June 21 for most northern hemisphere residents – after all, and this is the brightest day of the year. On the other hand, our world would be pretty dull if we were all twins … nothing against twins, of course, they are great!
But without the other eleven zodiac signs, something would only be missing. So as stupid as it is for the winter children to have to celebrate their birthday in the mud, cold, and six hours of daylight, it is probably for our best that birthdays are distributed all year round and more or less random.
 Nevertheless, we all share our birthday with so many other people – with a maximum of 366 days a year and more than 7 billion people on the earth, that is inevitable. Mathematically speaking, 50 people are at least 90 percent likely to have at least two of the birthdays on the same day. With 23 people it is at least 50 percent. However, when it comes to the question of how “mainstream” our date of birth is, it matters when exactly we saw the light of day – because according to a study by Harvard University from 1973 to 1999, some days are much more frequented than other.
September children are in good company.
The month with the highest birth rate by far is, therefore, September: According to the Harvard investigation, most people have birthdays on September 16, 19459007, the second-most on the 9th and third most on September 10. The Virgo zodiac sign has an above-average lobby in our society.
A relatively large number of birthdays are also celebrated in the surrounding months of July, August, and early October. The following figure provides an overview of the distribution of birthdays over the year. Dark brown tones stand for many birthdays, light ones for few (you can find an interactive graphic of this illustration at “vizwiz.com”).
Why is September so fertile?
If you are good at mental arithmetic, you are probably wondering why people produce children more often in December than in other months – because, from September nine months back, we land correctly in Sagittarius month. The answer to this question can, of course, only be guessed: Perhaps many people have intercourse in December instead of jogging outside.
Or to remove excess energy from all the cookies and chocolate they eat. Some may put Advent in the mood, others mulled wine, and others may not know how to get through the long nights … One thing is sure: in December there are many good reasons for many people to have intercourse. And as long as there is enough in the other months, we have no problem with it