Mr Sizer is a Consultant Obstetrician and Gynaecologist at The Shrewsbury and Telford Hospital NHS Trust and a Senior Lecturer at Keele University School of Medicine, where he has held an academic post alongside his clinical role since his appointment in 2007. He also serves as Medical Lead for Fertility Services within the Trust. He completed his specialist training in Wales in 2005, working under Mrs Sheila Walker, who established the first NHS IVF clinic. During this period, he also obtained an MD focused on male infertility in 2002, supervised by Professor Shaw, former President of the Royal College of Obstetricians and Gynaecologists. Alongside his clinical and academic responsibilities, he is Divisional Medical Director for Women’s and Children’s Services and Undergraduate Tutor for Women’s Health at Keele University’s Shropshire campus. His work extends into postgraduate medical education. He is Head of the Postgraduate School of Obstetrics and Gynaecology for NHS England in the West Midlands, overseeing specialist training across the region.