The higher oestrogen concentrations in women have been suggested as the reason for their slower development of atherosclerosis compared with men. Oestrogen receptors have been located on macrophages, smooth muscle cells, and endothelial cells in women and men, but it is not known whether the protective effect at the level of the arterial wall is mediated by these receptors. It has been reported that premenopausal women have fewer α oestrogen receptors in atherosclerotic than in normal coronary arteries. 1 The gene for human α oestrogen receptor contains a polymorphism in the regulatory (upstream) region of the gene: this polymorphism consists of a dinucleotide (thymine and adenine) repeat, the length of which has been associated with bone mineral density, suggesting an effect on oestrogen receptor transcription. 2 This prompted us to study whether this polymorphism is associated with coronary artery disease in men.