A Vatican official travelling in Mexico has condemned the country’s capital for legalising same-sex marriages, saying that such unions are only an imitation of heterosexual marriages.

According to Mexico El Universal, Father Gonzalo Miranda, a bioethics professor at Regina Apostolorum University, a pontifical institution, said: “A gay relationship is like decaffinated coffee, you do not wake up”.

Father Miranda, along with Monsignor Elio Sgreccia, president emeritus of the Pontification Academy for Life in the Vatican, is in Mexico to take part in a series of academic conferences.

The bishops criticised Mexico City’s new law at a press conference. Father Miranda said: “What just happened in California is very significant”, in reference to a federal judge’s recent ruling that overturned the state’s law prohibiting same-sex marriage, Proposition 8.

He continued: “On two occasions people spoke out against the legal recognition of gay marriage and twice a judge changed the popular vote with a ruling. In Mexico, I don’t know the mechanism used, but the people were not consulted [and] there wasn’t a referendum either.”

In December, Mexico City became the first autonomous municipality in Latin America to approve gay marriage.

However, the conservative federal government challenged the ruling, but the nation’s Supreme Court declared the law (which also allows gay couples to adopt) to be constitutional, and ruled that all Mexican states must recognize gay marriages made in the nation’s capital.

Both dignitaries said such unions went against nature, and that gay couples adopting children were not real parents but “substitutes” and that the law was “a grave injustice that cannot be described”.