The medical profession for convenience takes the gestation of a pregnancy from the first day of the mother's last period. In a four-week menstrual cycle, ovulation occurs two weeks after the first day of the previous period.
It is incorrect to assume that this baby was conceived on French soil. Conception would have taken place two weeks later than has been calculated by your "frantically diary-consulting" journalist. While a Statue of Fertility, masses of vintage champagne and a new era in Anglo-French relations would be much appreciated, this would be based on an incorrect assumption. Perhaps instead of libidinously charting the Blairs' diary, we should rather congratulate the couple, and wish them well with the attendant risks of older motherhood.
Dr TIMOTHY SEPHTON