les. The pigmentation in these areas can be influenced by sex hormones like estrogens and androgens. During pregnancy, the nipples, face, and abdominal wall become darkened. These areas of increased pigmentation during pregnancy are due to the increase in the production of estrogens. Anthropologists try to account for the fact that the genitalia are darker by suggesting that protection is needed against ultraviolet radiation damage, and has been thus evolved through natural selection.. This means that protection of the genitalia against forces that may preventreproduction was needed. Similarly, in this view, the pigmentation of the nipples during pregnancy would be a defense against ultraviolet radiation damage to the nipples. Supposedly, this type of protection would be needed while breast feeding during the early evolution of humans in Africa. According to Robins, 1991, darker pigmentation found in the genitals, may have evolved for the "protection of reproductive capacity", in that the pigmentation protects gametes within the genitalia from ultraviolet radiation damage. Variation of pigmentation within populations is sometimes greater than variation between populations. Comparisons of the European populations who inhabit the Mediterranean and those who reside in Scandinavia vary from dark skin, hair, and eyes to white pale skin, blue eyes, and red hair, respectively. These variations throughout the world are due to factors caused by the sun. The angle of sunlight hitting the earth varies with latitude. The higher the latitude, the lower the UV. Thus, in northern latitudes such as in Asia, there is lower UV radiation, and in southern latitudes, such as in Southeast Asia, Australia and India, there is higher UV radiation. Geography and climate has also been thought of as having factors in pigmentation variation. According to some, the cold weather in the temperate regions of the earth may have been a selective force against s...
