Applicants are also tested for HIV and screened for conditions such as depression, paranoia and 'gender confusion'.

Marianne Duddy-Burke, the executive director of DignityUSA, a Catholic gay rights group, said it was "impossible in this atmosphere" for celibate gay men to apply to the priesthood.

"The bishops have scapegoated gay priests because gays are an acceptable scapegoat in this society, particularly among weekly churchgoers," she said.

The church has never estimated how many of its priests are gay. Some Catholic scholars say that between 25 and 50 per cent of priests are gay, although other studies have found lower rates of homosexuality.