Harry's son makes history

16.10.13: HE MAY NOT be a royal, but he's special in a way that assures him a place in the medical textbooks.

For baby Stephen, born yesterday afternoon to Harry Windsor and his wife, Sarah, is the first child to have had changes made to his genetic blueprint only days after he was conceived. Without the changes, he would almost certainly have developed a form of diabetes.

"Before Harry and I got married we had a genetic test," said Sarah. "It showed that I am a carrier of the gene responsible for causing a type of diabetes and a range of related eye and heart disorders.

"We were told it was highly probable that any children we had would get the disorder. We were faced with the decision whether to risk having a diabetic child or to let doctors change the gene," she said.

"There have been concerns about the unpredictable effects of replacing genes," said Dr Hang Lau of Hammersmith hospital, "but we have done a lot of testing of this technique and were confident of a successful outcome."

Stephen was conceived outside the womb and after three days, when the embryo was composed of only eight cells, the defective gene was replaced.

"We also replaced one other gene that we know makes Alzheimer's di