G. Mark Insull was born in Invercargill and attended Otago Medical School, graduating MBChB in 1979. Following this he specialized in Obstetrics and Gynaecology obtaining his FRANZCOG in 1988. He spent four years in Oxford, England completing post graduate studies before commencing practice in Auckland in 1988. He has worked in full-time private gynaecological practice since 1996. Mark has a long term interest in Minimal Access surgery, performing both Laparoscopic and Hysteroscopic procedures in addition to general Gynaecological Surgery.
As at 2001, G. M. Insull was a Certifying Consultant in Auckland. Certifying consultants have the job of approving or disapproving a mother being permitted to have her pre-born child killed by abortion.