Pope Francis approved document on 31 October.
The Vatican's doctrine office has said that it is permissible, under certain circumstances, for transgender adults to be baptised as Catholics and to serve as godparents.
The Dicastery for the Doctrine of the Faith on Wednesday published a series of responses to questions from a Brazilian bishop regarding LGBT people and their participation in the sacraments of baptism and matrimony.
The document was signed on 31 October by Pope Francis and Argentine Cardinal Víctor Manuel Fernández, who heads the doctrine office, and the responses were published in Italian on the Vatican News website.
The Vatican's doctrinal watchdog said that transgender adults can receive the sacrament of baptism, as long as there is "no risk of causing a public scandal or disorientation among the faithful".
The document said that transgender people can be godparents at baptisms and witnesses at Catholic weddings, at the discretion of the parish priest who must excercise "pastoral prudence".
An individual in a same-sex relationship can also be a witness at a Catholic wedding, the document said, stipulating however that the person should "lead a life that conforms to the faith".
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