The Valençot family from Savigneux in Ain in eastern France are just coming to terms with the timely arrival of Charly last Thursday as an extra special birthday present to his brothers Alban (5) and William (3).
"It is unique in France. The doctors have no clear explanation. Also every time I gave birth by natural means," the boys' mother Severine Valençot told the Le Progrès daily.
And while somewhat less dramatic, the similarities don't end there.
"What's funny is, as for the first two, I had the same midwife and nurse. And they hadn't worked together for two years," Severine Valençot told the newspaper.
While the case may be unique in France, there have been similar incidences in Ireland and Scandinavia, according to the father Guillaume Valençot.
Alban and William meanwhile appear to have taken the news that they are to share their birthday with another sibling in their stride.
"They have already said that there will be some big parties," he joked, adding that they have been promised a birthday cake each.