This paper examines historical evidence for a quality-quantity trade-off between sibship size and height as an indicator of health. The existing literature has focused more on education than on health and it has produced mixed results. Historical evidence is limited by the lack of household-level data with which to link an individual's height with his or her childhood circumstances. Nevertheless a few recent studies have shed light on this issue. Evidence for children in interwar Britain and for soldiers born in the 1890s who enlisted in the British army at the time of World War I is reviewed in detail. Both studies support the idea of a significant trade-off, partly due to income dilution and partly because, in these settings, large families were a conduit for infection. Evidence from country-level time series is consistent with this view. The fertility decline that began in the late nineteenth century made a modest but nevertheless significant contribution to the overall increase in heights during the following half-century.