A new study that tracked three generations of nearly 2,300 animals from the San Diego Zoo, found that mammals portray an ability to select the gender of their offspring in order to bring gains to their species.
Researchers found that females do no exercise conscious choice, yet they possess the inherent capability to evaluate her health, the environment, quality of mate and decide what sex her child should be.
For instance, the safest bet for a lioness would be to have a girl. Even if her daughter is not the healthiest and powerful she will in all likelihood have at least the average number of cubs.
90 years of breeding records from 198 mammalian species were studied by the team to come out with the fundamental theory of evolutionary biology. This study also suggests the varying capabilities of different species.
Researchers said that the females appear to be the ones in control of the situation and the egg makes itself more conducive to a certain gender of sperm. This brings us to the question about what happens in human beings. Researchers feel that humans are certainly doing sex ratio manipulation, though research has failed to provide conclusive evidence.