The baby's mother, is due to give birth soon to the first British baby to have been screened to be free of a gene which can cause breast cancer.

The baby's parents decided to undergo the genetic screening because women in three generations of the man's family had been diagnosed with the disease in their 20's and any daughter born to the couple with the gene would have had a 50 to 80% chance of developing a certain breast cancer - the screening has prevented this happening.

The screening process 'pre-implantation genetic diagnosis' (PGD) involves taking a cell from an embryo at the eight-cell stage of development at around three-days old and testing it to guarantee that it does not have an altered gene.

PGD is already well-established practice for inherited diseases such as cystic fibrosis but experts warn the technique would not be suitable for everyone who has experience of breast cancer in their family.

In 2006, the Human Fertilisation and Embryology Authority allowed doctors to test for susceptibility genes, such as BRCA1 - though everyone carries a version of these genes, some particular variations of the genes greatly increase the risk of cancer.

Carrying the key BRCA1 mutation in this family's case would have given up to an 80% chance of developing breast cancer later in life - BRCA1 and a related version of another gene, BRCA2, account for around 5% of all breast cancers.

However not carrying an altered BRCA1 gene does not guarantee any daughter born to the couple would be unaffected by breast cancer because there are other genetic and environmental causes of the disease.

Many women who discover they have inherited one of the gene mutations choose to have a double mastectomy to remove their breasts.

The couple, who have chosen to remain anonymous, want to eradicate the gene flaw from their family as the husband's grandmother, mother, sister and a cousin have been diagnosed with the disease and while a daughter could have been affected by breast cancer herself if she carried the altered gene, a son could have been a carrier and passed it on to any daughters.

Fertility experts say the process stops the transmission from generation to generation and in future it may be possible to screen for any mutated gene which had been linked to a specific cancer.

Critics say it is possibly the first step towards 'designer babies'.