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MATERNAL AGE AT BIRTH DELIVERY, BIRTH ORDER AND SECONDARY SEX RATIO IN THE OLD ORDER AMISH OF LANCASTER COUNTY
Maternal Age at Delivery Birth Order Secondary Sex Ratio
2014/11/6
The observation that more boys were born than girls was noted in the late 1660’s. Recent studies suggest the secondary sex ratio (SSR) is declining in industrialized countries. SSR is proposed as a se...