The study was carried out by evolutionary geneticist Dr Maarten Larmuseau, of KU Leuven University, Belgium, who said that the figure was actually lower than was previously thought (file picture)

A shocking new study has revealed one in 50 British fathers may have unknowingly brought up another man's child - a figure lower than was previously thought.

Studies have previously suggested the figure could be as high as ten percent but in reality it is more likely to be between one and two percent, say scientists.

Evolutionary geneticist Dr Maarten Larmuseau, of KU Leuven University, Belgium, said: 'The observed low cuckoldry rates in contemporary and past human populations challenge the well known idea women routinely 'shop around' for good genes by engaging in extra pair copulations to obtain genetic benefits for their children.'

Some fathers' rights groups in Australia have called for mandatory paternity testing of all children at birth, with or without the mother's consent or even her knowledge.

But Dr Larmuseau and his colleagues say the emerging evidence consistently indicates just one in 50 fathers may have unknowingly raised children who were not biologically their own.

They say evidence for low rates of extra-pair paternity (EPP) challenges the notion that it pays, evolutionary speaking, to sleep around.

When they first began exploring the issue they were surprised how little hard evidence there was.

Despite that, the scientific literature frequently suggested about one in ten of all children would have a biological father different from the alleged one.

But reliable data on contemporary populations have become available over the past decade, mainly as supplementary results of medical studies.