Julie Brill writes: >I also grew up believing that it was a good thing that my generation began >getting our periods earlier than our moms and grandmoms. We were told this >was due to better nutrition. I think now though that it's related to all >those growth hormones in our food supply?! The process known as "positive secular trend" in which children grow faster and end up taller and have their menstrual periods earlier when environmental conditions change to better nutrition and less disease -- is found whenever and whereever nutritional stress is removed, either from better diet or fewer diseases/parasites to cope with. Lower age at menarche (first menstruation) is found in all populations where the diet in childhood improves, including many places where there are no growth hormones in the food supply. Thus, there is very little evidence that these hormones affect humans. Also human growth hormone is biochemically very different from bovine growth hormone, and there is no evidence that bovine growth hormone can affect human growth. In fact, you have to have either real or synthetically manufactured *human* growth hormone in order to treat human children with growth hormone deficiency. You can't just give them cow growth hormone because it has no effect. There are other reasons to not like the use of bovine growth hormone in cows, but worrying about your children going through puberty too soon shouldn't be one of them. ---------------------------------------------------------------------------- ------- Katherine A. Dettwyler email: [log in to unmask] Anthropology Department phone: (409) 845-5256 Texas A&M University fax: (409) 845-4070 College Station, TX 77843-4352