Caracas, Venezuela ? Opponents of President Hugo Chavez are demanding a review of what they call gross irregularities in the voter registry, pointing to a western state where 1,921 people by the name Gonzalez are listed with the same date of birth.

The case of the many Gonzalezes in Zulia state was reported by Roberto Ansuini, an opposition-aligned researcher and former member of the National Electoral Council.

He said he discovered the Gonzalezes by using a computer database to analyze more than 2 million new voters signed up since 2003. Their first names ranged from Armando to Victor, but each one turned 32 on March 15 and all were from Zulia, according to the list compiled by Ansuini.

The name Gonzalez is ubiquitous in Venezuela, but Ansuini says citizenship records show no more than 89 people of the same last name have been born on any other day. He said that suggests possible manipulation.