VATICAN CITY — The Legion of Christ religious order, still reeling from 2009 revelations that its late founder was a pedophile who fathered three children, was hit Tuesday by another scandal after its most well-known priest admitted he had fathered a child several years ago.

The Rev. Thomas Williams, a moral theologian and prominent American author, lecturer and television personality, said in a statement he was “deeply sorry for this grave transgression” against his vows of celibacy. He said he would be taking a year off to reflect on what he had done and his commitment to the priesthood.

The revelation immediately raised questions about when Williams’ superiors knew of the existence of the child, given that the birth occurred several years ago and that Williams, a former superior of the order’s Rome headquarters, has never stopped speaking out on issues of moral conscience. A Legion spokesman said the order had decided not to disclose when it learned about his child.

Williams’ admission was issued after The Associated Press last week presented the Legion with the allegation against Williams, which was lodged by a Spanish association of Legion victims. The association’s accusations, sent to the Legion and Vatican several weeks ago, also named other Legion priests accused of sexually abusing minors.

Williams, who was not accused of abuse, said that “a number of years ago” he had a relationship with a woman and fathered her child. He didn’t identify the mother and didn’t say whether the relationship was over. He also did not identify the gender or say if he was helping to support the child.

The Legion has been beset by scandal following revelations that its late founder, the Rev. Marciel Maciel, fathered three children with two women and sexually abused his seminarians. Maciel died in 2008, and in 2009 the Legion admitted to his crimes. The Maciel scandal has been particularly sensational given that the Mexican-born priest was held up by Pope John Paul II as a model for the faithful, with his priests admired for their orthodoxy and ability to bring in money and attract new seminarians.