A British woman has conceived the first baby guaranteed to be free from hereditary breast cancer. Doctors screened the woman’s embryos for the BRCA-1 gene. The couple produced 11 embryos of which five were found to be free from the gene. Two of these were implanted in her womb and she is now 14 weeks pregnant.

Tests on the 11 embryos were conducted by removing just one cell when they were three days old. Two embryos that were free of the gene were then implanted resulting in a single pregnancy.The woman and her husband had to go through in vitro fertilisation in order to create embryos that could be screened. They have also been able to freeze two screened embryos for future use.

The couple decided to have their embryos screened because the husband had tested positive for the gene and his sister mother grandmother and cousin have all had breast cancer.

About 5% of the 44,000 cases of breast cancer diagnosed in Britain each year are estimated to be caused by the BRCA-1 and BRCA-2 genes both of which can be detected in embryos. Having the BRCA-1 gene means there is a greater than 50% chance of developing breast cancer. In addition to breast cancer, women carrying the gene also have a higher risk of ovarian cancer and male carriers are at greater risk of developing prostate cancer. Experts say thousands of cases of breast cancer could be avoided by screening embryos using the technique called preimplantation diagnosis (PGD).

Only one other woman – an Israeli mother-to-be – is thought to have become pregnant after undergoing the embryo screening.