MEN MAY SHARE MORE GENES WITH SISTERS’ KIDS THAN CHEATING
WIFE’S KIDS
A University of Utah study produced new mathematical support
for a theory that explains why men in some cultures often feed and care for
their sisters’ children: where extramarital sex is common and accepted, a man’s
genes are more likely to be passed on by their sister’s kids than by their
wife’s kids.
The theory previously was believed valid only if a man was
likely to be the biological father of less than one in four of his wife’s
children – a number that anthropologists found improbably low.
But in the new study, University of Utah anthropology Professor
Alan Rogers shows mathematically that if certain assumptions in the theory are
made less stringent and more realistic, that ratio changes from one in four to
one in two, so the theory works more easily.