The Vatican has revealed that it has secret rules for priests who father children despite their celibacy vows, The New York Times said in a report.
The Vatican has confirmed that its department overseeing the world's priests has general guidelines for what to do when clerics break celibacy vows and have children, the report said.
"I can confirm that these guidelines exist," Vatican spokesman Alessandro Gisotti told The New York Times. "It is an internal document."
The confirmation comes after Vincent Doyle, a psychotherapist in Ireland, told the daily that he was 28 when he learned from his mother that the Roman Catholic priest he had always known as his godfather was in truth his biological father.
The discovery led him to create a global support group, Coping International, to help other children of priests like him.
When he pressed bishops to acknowledge these children, some church leaders told him that he was the product of the rarest of transgressions.
In 2017, Archbishop Ivan Jurkovic, the Vatican's envoy to the UN in Geneva, finally showed him a document of Vatican guidelines for how to deal with priests who father children, proof that he was hardly alone.
According to the Archbishop, these children are termed "children of the ordained", Mr Doyle told The New York Times.
Mr Doyle said when he had asked for a copy, the Archbishop refused, saying it was secret.
The development comes as the Vatican prepares for a meeting on Thursday on the ongoing child sexual abuse crisis.
According to The New York Times, the children are sometimes the result of affairs involving priests and laywomen or nuns and others of abuse or rape.
There are no official estimates of how many such children exist. But Mr Doyle told The New York Times that his support group website has 50,000 users in 175 countries.
The tradition of celibacy among Roman Catholic clergy was broadly codified in the 12th century, but not necessarily adhered to, even in the highest places.
Rodrigo Borgia, while a priest, had four children with his mistress before he became Pope Alexander VI, an excess that helped spur Martin Luther's Protestant Reformation.