Michael Bisping says he knows of a 16-year-old high school phenom who could destroy Floyd Mayweather AND Conor McGregor in a fight ... and they happen to share the same last name!!

We spoke to the UFC middleweight champ about the super fight ... and while Bisping says he'd be too big of a mismatch to take on Floyd or Conor ... he guarantees his son, Callum, could do the job and "beat the f**k outta the pair of 'em."

BTW -- Callum is already a stud in his own right ... having won the silver medal at the SJJIF world jiu-jitsu championships last year. He also won top sophomore on his high school wrestling team. 

Bisping explains that Floyd and Conor are both amazing fighters ... but their size differences would be too much of an advantage for his offspring.