An Interview with Professor Malcolm Ferguson-Smith who is is Emeritus Professor of Pathology, University of Cambridge. He graduated in medicine at Glasgow University in 1955 and, while undertaking postgraduate training there in pathology, was introduced to research on sex chromatin under Bernard Lennox. An interest in Klinefelter’s syndrome in 1957 to 1958 led to his appointment as Fellow in Medicine at Johns Hopkins University, Baltimore, in 1959, where he established the first chromosome diagnostic service in the USA and undertook cytogenetic research into Turner syndrome. Research interests include molecular cytogenetics, karyotype evolution, vertebrate sex determination and comparative genomics. He is a joint author of Essential Medical Genetics. The interview is part of the History of the Modern Biomedicine Interviews (Digital Collection).