Fertility of Nepalese Sherpas at moderate altitudes: comparison with high-altitude data.

Data are reported on ages at menarche, first marriage and first childbirth and on completed fertility, in Sherpa populations of Nepal at moderate altitude (2200-2600 metres). Comparison of these data with similar data from two high-altitude surveys (Weitz et al. 1978, Gupta, 1978) indicates that cultural factors, examined in detail by Weitz et al. (1978), are probably insufficient to explain the lower completed fertility in high-altitude Sherpas. It is concluded that this lower fertility is mostly attributable to lower fecundity, and partly to the later mean age at first childbirth and the higher proportion of celibate nuns in high-altitude Sherpas.