Research by the University of Sheffield has found that the number of infants born in England and baptized into the Church of England dropped to 21% in 1999.
David Voas, a demographer at the university´s department of sociology, claims that the minority status of Anglicans threatens the foundations of the church´s establishment.
The Church of Ireland and the Church of Wales were both disestablished on the grounds that they served only a minority of the population.
In the Church of England, fewer than a million people regularly worship on Sundays, but among the over-50s in the country some 70% are baptized Anglicans.
The findings show that there was almost universal baptism before World War II with 75% of babies christened in the Church of England in 1933. But since the war, with the exception of 1950, the number of baptisms has declined.
Babies born to two Anglican parents remain the most likely to be baptized in the Church of England, the study says. Voas estimates that 24 million of the 48 million people living in England this year were baptized Anglican -- 49.8% of the population.
He predicts that this figure will decline at a rate of a million every five years as older people die and fewer of the young are baptized.
A spokesman for the Church of England challenged the validity of the research.
"Baptism introduces people into the Christian family and not into any particular denomination and so it is difficult to calculate how many end up as Anglicans," he said.
He dismissed the claim that a smaller church raised the case for disestablishment. He said: "People of all faiths appreciate the fact that an established Church of England means faith has a place at the center of the state."