Couple devoted to baby made to save firstborn

An Australian couple who created medical history and sparked a storm of controversy over their decision to have a "designer" baby to save the life of their seriously ill son have spoken out about their choice.

The Tasmanian couple, known only as Stephen and Leanne, welcomed their life-saving baby boy, C.J., last month.

C.J. was conceived using the contentious technique called PGD (Preimplantation Genetic Diagnosis) in which embryos are screened for genetic disorders before being implanted in the mother's uterus.

While debate rages over the ethics of so-called "spare parts" babies, for Stephen and Leanne it provided the only lifeline for their four-year-old son B.J. who suffers from a rare immune deficiency known as hyper IgM syndrome.

B.J.'s condition, which affects about 30 children in Australia, meant he had almost no immune system, leaving him open to serious infections.

His only chance at leading a normal life was a bone marrow transplant but no one in his family could provide a direct tissue match. So Stephen and Leanne made the difficult decision to conceive a child that would be free...