As IVF moved from an NHS-supported activity in the UK to private free-standing facilities, fees and careful financial management were required. The underlying fertility profiles became expanded and the age-range of patients were extended. To avoid patient anguish if a live birth was not achieved, IVF clinics moved away from natural cycles to increasingly orchestrated regimens including manipulations. The ICSI procedure was initially introduced for male factor due to suboptimal semen profiles, but soon expanded to cases of surgical sperm recovery, thereafter to non-male factors including unexplained infertility, followed by ‘precious’ scenarios to avoid the risk of failed fertilisation. Concerns that ICSI by-passes the numerous physiological processes of natural fertilisation remain, but worldwide application over more than 25 years indicates that the technique does not cause congenital or developmental abnormalities. Applying an IVF-ICSI Split model for new cases with unexplained infertility optimises blastocyst numbers with an ICSI rate of ~90%.