A public notary in the Brazilian state of Sao Paulo has approved a civil union between three people, Globo TV reported.
The decision by Claudia do Nascimento Domingues to grant the wishes of the man and two women has sparked controversy in the South American country, where most people are Catholic.
The three adults have lived together in Rio de Janeiro for three years and have a joint bank account, The Telegraph reported.
Domingues says there is nothing illegal about the arrangement.
“We are only recognizing what has always existed. We are not inventing anything,” Domingues said.
“For better or worse, it doesn’t matter, but what we considered a family before isn’t necessarily what we would consider a family today.”
But the civil union has shocked religious groups and social conservatives in the country.
Regina Beatriz Tavares da Silva, a lawyer, told the BBC it was "absurd and totally illegal", and "something completely unacceptable which goes against Brazilian values and morals."
The Christian Post quoted Marisa Lobo, a psychologist and evangelical Christian, as saying: “Jesus, come back soon.”
Brazil has legally recognized same-sex unionssince 2004. The civil unions can be converted into marriage with the approval of a state judge.