Mexican electoral authorities said Tuesday they are investigating 17 male candidates who allegedly registered as transgender to avoid a gender quota in local races in the southern state of Oaxaca.

Oaxaca requires gender parity — equal numbers of male and female candidates — in local races. But the state also states that "the candidacy will be registered to the gender with which the candidate self identifies."

The state electoral council said parties for the candidates under investigation filed registration documents that "indicated their desire to be registered as transgender women."

The scheme was detected in part because of complaints from a traditional Oaxacan transgender community that dates back centuries to pre-Hispanic times, known as muxes (MOO-shays).

They said that 17 of the 19 candidates registered as transgender — some dressed as muxes — weren't really part of the community. They said the other two were.

The state electoral council statement said the candidates could be barred from running and their parties fined.

The men are running for the posts of mayor or assistant mayor for the ruling party and a right-left coalition.

"The majority of them have publicly known marriages and children with women," a coalition of muxe and women's rights groups said in a statement. "Some of them are even running for re-election as mayors, and during their past terms they said nothing about being transgender."

"We reject this fraudulent usurpation of trans identity meant to avoid the obligation of the parties and the candidates to respect the constitutional mandate of gender equality,' the coalition wrote.