THE GIRL is cross with me for having a birthday so close to Mother’s Day.

She is, I fear, feeling the responsibility of being the only child left at home.

“Dad’s just as bad,’’ she said the other night. “His birthday’s always next to Father’s Day.”

I apologised profusely for our shortcomings but pointed out that there’s really little we can do about this situation, short of adopting official birthdays like the Queen.

Her own birthday, I have dared to venture, falls right in the middle of what I call the birthday season, when we have something like eight family celebrations within a two week period. It is a time when I have to ensure a seamless supply of birthday cards and gifts.

But, of course, this is my fault as well because I chose to have both my children at the same time of year and married someone who was also a mid-summer baby. In fact, Secondborn was due on Firstborn’s birthday but, in the end, was delivered early by an elective Caesarian section.

The Man has the same summer birthday as his mother and, as it turns out, this date is also shared by Firstborn’s girlfriend.

Stepping out of the family, three of The Boy’s closest friends share his birth date so he’s not short of astrological twins either.

The odds of finding someone with the same birthday as yourself are not as poor as you might think, particularly if you are a summer baby because more infants arrive in June, July and August than in other months of the year.

In probability theory, I have discovered, the birthday paradox says that in any random group of 23 people there is a 50% probability of finding someone with the same birthday (please don’t ask me to explain this) so perhaps all these summer birthdays in one family are nothing special after all.