Constantino's was born with a right arm that is intact down to the wrist but, after that, his "fist" tapers to a nub.
The Queens native — who probably has had the chance to tell people I could beat you with one hand behind my back more times than he'll admit — will be making his pro debut Saturday in a pay-per-view event in Brooklyn after a ten fights as an amateur.
There is no record of a one-handed pro in the history of New York boxing but that won't stop Constantino from trying to make a two-fisted statement in the ring.
"There's definitely a lot of pressure on me to perform well," said Constantino. "I want to win and show people that if you put your faith in God that anything is possible."
The single-handed light heavyweight is no gimmicky attraction and has proved his mettle by making the Golden Gloves (video) quarterfinals in 2002 and even knocked out one opponent earning him a "Fighter of the Night" award.
Constantino's right glove hangs about a foot shorter than his left and he usually only uses it to block from his right-handed stance. His left jab and hook are what keeps him in the game.
You think opponents would be lining up to take advantage of his physical challenge, but that's not the case.
"Nobody wanted to give him an opportunity," said boxer Sadam Ali, who will be promoting and headlining Saturday's show. "He's bringing something new to boxing. That's how I look at it. It's a beautiful thing to me."
The event's matchmaker, Felipe Gomez, had a difficult time finding someone who would take on the ultra-unorthodox — is he a southpaw with a righty stance or a righty with only a left? — fighter
Rhode Islander Nathan Ortiz (0-2 as a pro) finally said he would answer the opening bell but thought Gomez was kidding at first.
"He thought I was joking when I told him I was fighting someone who had only one hand," said Gomez. "But he took the fight. He's 0-2. I guess he's looking for any advantage he can get."
People who have seen Constantino in the ring say opposing boxers shouldn't drop their left guard too quickly.
"He can fight. He knows what he's doing, but how can you not see the left-hand coming if you're his opponent," said Bryan Adams, the Golden Gloves director. "Because he knows how to fight. He can punch"
Update: Fighter wins in pro debut
Michael Constantino's pro boxing debut ended in odd fashion but the one-handed fighter was left standing in the ring with his good hand held high in victory.
The Brooklyn fighter used a looping left to cause his opponent Nathan Ortiz to stagger back to his corner and complain that he was fatigued. After a few moments, when referee Randy Neumann concluded that Ortiz didn't want to continue, he halted the fight at 1:16 of the second round giving Constantino a TKO victory.
Constantino, who fought at cruiserweight, attracted a lot of attention from fight fans and the New York State Athletic Commission respectively.
The 33-year-old boxer had to go through extra pre-fight physicals and wrap his hands for officials the day before the fight to see how he would be covering his congenially damaged right hand.
The only special attention Constantino ever wanted was from other people who face the world everyday with physical challenges.
"I just wanted to show people that in life, if you ever feel like you're not good enough or you feel down, that anything is possible," he said after the fight.
It sounds like Constantino had two victories in a single fight last night.