Mammals can 'choose' sex of offspring, study finds

[unable to retrieve full-text content]A new study shows that mammalian species can "choose" the sex of their offspring in order to beat the odds and produce extra grandchildren. In analyzing 90 years of breeding records from the San Diego Zoo, researchers were able to prove for the first time what has been a fundamental theory of evolutionary biology: that mammals rely on some unknown physiologic mechanism to manipulate the sex ratios of their offspring as part of a highly adaptive evolutionary strategy.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/~3/ZRJXs7qIZGM/130710182941.htm

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