SummaryAn Indian sample of 277 twins has been analysed with a view to assessing the influences of certain factors on birth weight and survival. The twin birth rate shows an increasing trend with parity as well as with maternal age, the overall rate being 1 in 59. Males have higher mean birth weight than females. The means of birth weight, parity and maternal age are higher for unlike‐sex twins than those for the other group. The trend of birth weight over parity for given maternal age seems to be curvilinear. No consistent trend of the same with maternal age, parity fixed, emerges. Birth weight of one twin seems to have linear regression on that of the other. Mortality is highest for the first‐born. The trend of the rate of mortality over maternal age is highest at the lower and upper groups with a minimum in the age group 28–32. Neither sex nor group is found to have a significant differential effect on sur
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