DR G. Moscoso/Science Photo Library
A marked fall in the number of babies born with inherited illnesses is possible, as a pre-pregnancy DNA test is used more widely.
The test checks whether prospective parents carry genes that, if both pass a copy to their child, will cause disease, known as a recessive condition. The test is usually only offered to people who know that recessive disorders such as cystic fibrosis run in their family.
But most carriers of these genes don’t have any such warning, says Alison Archibald …