Wikipedia says “Sociobiology is a field of biology that aims to examine and explain social behavior in terms of evolution.”
One of the things that we learned about on our Northwest Passage cruise was the historical practice of female infanticide among Eskimos/Inuits. When food got scarce, female infants were at risk. The explanation given in museums and by guides was that boys would grow up into adult male hunters who could take care of their elderly parents.
The difficulty of procuring nourishment frequently induces the women of this tribe to destroy their female children. Two pregnant women of the party then at the fort, made known their intention of acting on this inhuman custom, though Mr. Dease threatened them with our heaviest displeasure if they put it into execution: we learned that, after they left us, one actually did destroy her child; the infant of the other woman proved to be a boy.
If the goal of an animal is propagating his/her/zir genes, this does not seem to make sense. A typical human female reproduces, thus passing on her parents’ genes. A typical human male has no offspring (polygamy is the natural human state, it seems; see “The era of monogamous long-term marriage was a brief interruption” within Real World Divorce).
The period of life in which the son will be potentially useful won’t likely start until after the parents are beyond reproductive age (and therefore whether they live or die has minimal effect on their reproductive success).
Readers: Is the existence of female infanticide across a range of cultures a simple proof that sociobiology is wrong?