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Authors' reply

BMJ 1995; 311 doi: (Published 26 August 1995) Cite this as: BMJ 1995;311:570
  1. Niels Keiding,
  2. Niels E Skakkebaek
  1. Professor Department of Biostatistics, University of Copenhagen, DK-2200 Copenahgen, Denmark
  2. Professor University Department of Growth and Reproduction, Section GR-5064, Rigshospitalet, DK-2100 Copenhagen, Denmark

    EDITOR,--As Alexander Lerchl points out, figure 1 of our overview indicating that sperm concentrations have decreased during the past 50 years is deficient. During the final preparation for publication, for reasons that we cannot trace, some of the points were omitted. The regression analysis in the paper is unaffected by this: the new regression line (weighted by the number of subjects) had a slope of −0.934x106/ml per year (SE 0.157; P<0.0001), and that line was correctly included in our original figure. A better impression of the regression analysis is provided by the figure in this letter, in which the areas of the …

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