Maternal Age At Birth Delivery, Birth Order And Secondary Sex Ratio In The Old Order Amish Of Lancaster County
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 sentinel for reproductive health. Declining SSR may reflect environmental factors or other influences...
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| Format: | Others |
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ScholarWorks@UMass Amherst
2013
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| Online Access: | https://scholarworks.umass.edu/theses/1073 https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=2189&context=theses |