Dr. Cees N.M. Renckens (1946) studied medicine at the state university of Groningen and qualified in 1971. After two years of preparation he worked two years as a tropical doctor in Zambia in the Ndola Central Hospital, in the surgical and obst/gyn. departments. After his repatriation he specialised in obstetrics and gynaecology in the academic hospital of the Amsterdam university. Since 1980 he is working as a gynecologist in the Westfries Gasthuis in Hoorn, having a special interest in infertility and endocrinology.
In 1980 he joined the Union against Quackery, an organisation that was founded in 1880, which after a period of crisis around 1976 developped new vigor in a response to the rise of alternative medicine that started around 1973. Since 1988 he is chairman of that Union with a present membership of around 1400 people. He is author of many publications on quackery and alternative medicine, mainly in Dutch. He wrote three books: 'Contemporay quackery' (1992), 'Quacks in potassium hydroxide' (2000) and 'It cannot be called healing. Sketches of the twenty most notorious healers of the 20th century' (2001). In 2004 he successfully defended his thesis at the Amsterdam university Wrong tracks in medicine (Dwaalwegen in de geneeskunde) in which he dealt with quackery, alternative medicine and fashionable diseases.
He is married and has two children.