Lazio have threatened to take legal action against those who dispute the age of their 17-year-old midfielder Joseph Minala.
Minala has been criticised on social media this week and called an 'age cheat'. He was also forced to deny telling Senegalese media he was 41, and would turn 42 in August.
Serie A side Lazio say the Cameroonian's birth certificate is 'absolutely legitimate'.
"We reserve the right to take action against those responsible for the protection of the good name of the company and the footballer," Lazio said in a statement.
Minala joined the Italian club in December and responded to his critics, tweeting: Envy is the weakness of man, and those with a poor soul hurt others when you are in Serie A. Love you! Forza Lazio."
The player also issued a statement, saying: "I have read the alleged statements in which is says I confessed my real age was different to what was stated in my [official] doucments.
"They are false statements that have been attributed to me by people who do not know."