Christopher Pekny, 28, was building the device when it exploded just before midday on Sunday.
The police said the explosion killed Mr Pekny and injured his brother Michael Pekny, 27, who was also taken to hospital.
Gender-reveal parties are celebrations where expectant parents announce whether they’re expecting to have a girl or a boy and they’re growing in popularity. Viral videos on social media show extravagant ways of revealing the gender and becoming more and more elaborate.
Police have not specified what device caused Sunday’s explosion. New York’s state police department and its bomb disposal unit are investigating the accident.
Speaking to a local newspaper, Mr Pekny’s oldest brother, Peter Pekny Jr, described what happened as “the freakiest of freak accidents that I could ever imagine“. He did not know what had caused the explosion.
The death is the latest in a few recent accidents linked to gender-reveal parties in recent years.
They can include prediction games, with the “big reveal” being made with fireworks and coloured smoke grenades.