Forest Ranger started the day as a colt but won Wednesday's Earl of Sefton Stakes at Newmarket as a gelding after a pre-race inspection by the veterinary officer revealed something was most definitely amiss.
Richard Fahey's four-year-old was listed incorrectly as a colt in racecards but had in fact undergone a recent gelding operation which the trainer had failed to report.
Nevertheless, it appeared to have a beneficial effect as he scored on his seasonal reappearance for the third time in a row in the 1m1f Group 3 under Tony Hamilton.
Racing prominently behind the keen Frankuus, Hamilton unleashed Forest Ranger with just over two furlongs to go and, after a protracted duel with the Aidan O'Brien-trained Deauville, he stuck his nosebanded head in front to take the prize by half a length.
Sent off at 8-1, the big son of Lawman always looked likely to deny the Ryan Moore-ridden favourite and the first two came clear of Euginio, who stuck on well to take third.
On the failure to report the gelding operation, Fahey, who was winning the Earl of Sefton for the first time, said: "I only discovered the girls in the office hadn't declared he was a gelding this morning, but we now have the money to pay the fine if there is one."
There is indeed likely to be a fine, with BHA spokesman Robin Mounsey confirming: "It is the trainer's responsibility to inform Weatherbys about the change and in such circumstances this will go through a disciplinary panel and, generally, the penalty is a fine."