Mrs Lymberis and her husband, Mark, endured five years of unexplained infertility, an ectopic pregnancy and countless failed IVF attempts before she heard about Dr Sacks' pioneering research.

After tests revealed Mrs Lymberis' body had higher than normal levels of natural killer cells, she went on a course of immunosuppressant drugs.

Two IVF attempts later she was pregnant with daughter Tiana, who turned two yesterday.

Mrs Lymberis is now 37 weeks pregnant with her second child, who was conceived with the help of steroids to control her body's over supply of natural killer cells while she underwent a round of IVF.

Despite the lack of concrete medical proof, she has no doubt Dr Sacks is to thank for her two miracle babies.

"It's 100 per cent because of him,'' she said. "If it was not for him we would have no children at all, I have no doubt in my mind.

"I thought I was never going to have children. Two is a blessing.''