Infidelity may be natural according to studies that show nine out of 10 mamals and birds that mate for life are unfaithful. Experts found animals that fool around are only following the urges of biology. New studies using genetic testing techniques show that even the most apparently devoted of partners often go in search of the sexual company of strangers. Females stray to gather the best possible genes for their offspring, while males are driven to father as many and as often as possible. True monogamy actually is rare.
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