I showed her the remains of the blood-stained singlet from Jarman’s Gym with the sample square cut out of it. There would be no need to test the handkerchief that had wiped Margaret Case’s tears.

Ultimately, the entire father problem was caused by Gene. He almost certainly taught the medical students an oversimplified model of the inheritance of common traits. If Rosie’s mother had known that eye colour was not a reliable indicator of paternity, and organised a DNA test to confirm her suspicions, there would have been no Father Project, no Great Cocktail Night, no New York Adventure, no Reform Don Project – and no Rosie Project. Had it not been for this unscheduled series of events, her daughter and I would not have fallen in love. And I would still be eating lobster every Tuesday night.

Incredible.