Lazio have threatened legal action against anybody else who claims that their youth-team player Joseph Minala is older than 17.
Minala, who was called up to the Lazio first team for the first time by coach Edoardo Reja for last Sunday's derby with Roma, has been subjected to reports he is older than he declares himself to be.
The Cameroonian was born on Aug. 24, 1996, but it has been suggested he looks older in photographs that have surfaced on the internet, including what is thought to be his own Twitter account.
In an attempt to bring an end to the allegations, Lazio announced on the club's official website that they "confirm the absolute legitimacy of the paperwork filed with the federation and denounce the latest attempts, from hostile domains, to cast a sinister light over the club's operations.
"From now on, [the club] announces that it will take any action aimed at ending such behaviour out of respect for the fans and the player while reserving the right to take action against anybody responsible [for such behaviour] to defend the good name of the club and the footballer."
Earlier on Wednesday, the player's agent, Diego Tavano, told La Gazzetta dello Sport: "If you talk to him, then you realise from the way he speaks that he's still absolutely a 17-year-old lad. Joseph had a difficult childhood, that's the issue."
Minala arrived in Italy three years ago and was spotted by Lazio's talent scouts when he won the Trofeo delle Regioni 2013 as part of a representative of the state of Lazio.
He was playing for Vigor Perconti at the time and their owner Maurizio Perconti said: "I cannot deny that he looks older than he is, but his paperwork is all genuine."