The presence of the “ginger gene” has become so important for some people, they are taking DNA tests to see if they are carrying it.
The organisers of a heritage show are planning to set up simple DNA tests for couples at an exhibition in the UK next month.
They are bracing themselves for the influx of couples who will be keen to find out their chances of producing red-headed children.
Carriers of the gene variant can have ginger children even if neither parent has red hair.
Television show Who Do You Think You Are? Live are due at the Olympia in London to carry out the tests.
Finding out if you could have a kid with red hair has become so important parents-to-be are checking if they are carrying the ginger gene.
Dr Jim Wilson, chief scientist at BritainsDNA, the ancestry company behind the test, said: “Through a simple saliva test to determine deep ancestry, we can also identify whether an individual is a carrier of any of the three common red-head variants in the gene MC1R.
“This means that families can carry a variant for generations, and when one carrier has children with another carrier, a red-headed baby can appear seemingly out of nowhere.”
It is estimated that about four in ten people carry the red-head gene variant without having red hair themselves.
About 40 per cent of men and women in Ireland carry a red head variant, but only 10 per cent actually have red hair.
In Scotland, just over 30 per cent are known carriers and up to 13 per cent have red hair, while in England only 6 per cent of people have red hair.
On the Continent, only about 1.3 per cent of people are red-headed and the natural hair colour gets much rarer heading east.
Looking at the world population figures, only 0.5 per cent have red hair. This is nearly 40 million people.
