The contraceptive pill is polluting the environment and is in part responsible for male infertility, a report in the Vatican newspaper L'Osservatore Romano said Saturday.
The pill "has for some years had devastating effects on the environment by releasing tonnes of hormones into nature" through female urine, said Pedro Jose Maria Simon Castellvi, president of the International Federation of Catholic Medical Associations, in the report.
"We have sufficient evidence to state that a non-negligible cause of male infertility in the West is the environmental pollution caused by the pill," he said, without elaborating further.
"We are faced with a clear anti-environmental effect which demands more explanation on the part of the manufacturers," added Castellvi.
The article was promptly dismissed by several organisations.
"Once metabolised, the hormones contained in oral contraceptives no longer have any of the characteristic effects of feminine hormones," said Gianbenedetto Melis, vice-president of a contraceptive research association, quoted by the ANSA news agency.
The hormones contained in the pill such as oestrogen "are present everywhere... in plastic, in disinfectants, in meat that we eat," added Flavia Franconi, of the Society of Italian Pharmacology.
Pope Benedict XVI in October reaffirmed the Roman Catholic Church's condemnation of artificial birth control.
Contraception "means negating the intimate truth of conjugal love, with which the divine gift (of life) is communicated," the leader of the world's 1.1 billion Roman Catholics wrote on the 40th anniversary of a papal encyclical on the topic.
An encyclical is a letter usually treating some aspect of Catholic doctrine and issued occasionally by the pope.
The landmark document, whose title in English is "On the Regulation of Birth", was published at a time when the development of the Pill was giving new sexual freedom to women across the world.
Millions of Catholics distanced themselves from Rome as a result.