Gab is a reproductive gynaecologist, with interests in subfertility, IVF, donor insemination contraception and the menopause.

He is part of the original MonashIVF team that produced the world’s 4th -13th IVF babies. He is a Life Member and past President of FSANZ, Life Member and Past President of Family Planning Australia, and a past Councillor of RANZCOG. He has published over 160 scientific papers, and 60 book chapters. He has also Edited 15 textbooks for Cambridge University Press, and written 6 books for the public. He is Foundation Editor of the ASPIRE journal, Fertility and Reproduction.