Short made outstanding contributions to knowledge of the comparative endocrinology of reproduction in domestic, laboratory and wild animals, and in humans. Initially he was concerned with development of methods for the isolation and measurement of steroid hormones in blood and tissues in different reproductive states. That led to study of control of testicular activity in seasonally breeding animals and the influence of hormones on behaviour. More recently he has investigated human reproduction with particular emphasis on the way in which lactation regulates fertility in women, and the ways in which this could be exploited in developing countries to check population growth.