Dennis Styne, MD, wrote in his chapter "Puberty" in the 2007 book Greenspan's Basic and Clinical Endocrinology:
outbreak of gynecomastia [development of enlarged breasts in males] in
boys and precocious thelarche [premature development of breast buds in
females] in girls in Bahrain was traced to ingestion of milk from a cow
given continuous estrogen treatment by its owner to ensure
uninterrupted milk production."
Linda Folden Palmer, DC (Doctor of Chiropractic), wrote in her May 1999 article in Dynamic Chiropractic, "Coming of Age in America (Much Too Soon)":
in the U.S. and other industrialized nations are now reaching puberty
at drastically earlier ages... Two factors proven responsible for
precocious puberty are detached parenting and consumption of cow's
milk has a high fat content, high levels of biologically available
hormones and growth factors, and other chemical contaminants from
highly medicated cows fed environmental trash. These are all linked to
Diane Marty, a journalist, wrote in her Apr. 30, 2007 article "Empowered Shopping Tips From the Green Side of the Aisle," for E: The Environmental Magazine:
don't recognize the importance of organic dairy products... More and
more evidence points to a relationship between hormones in milk and
early puberty in teens, preteens and even grade schoolers. If you buy
only one organic item for your kids, make it milk."
The American Council on Science and Health stated in their June 2001 publication "The Role of Milk in Your Diet":
"Experts aren't sure whether girls really are entering puberty earlier. If they are, the most likely explanation is that today's girls are heavier than their mothers were at the same age. Puberty tends to occur earlier in heavier girls.
There is no research demonstrating that milk or dairy products play a role in early puberty. Milk has always contained hormones in very small amounts; their presence is not a result of any changes in animal husbandry practices. Today's girls drink less milk than their mothers did. Thus, it seems very unlikely that milk is responsible for any change in the age at which girls enter puberty."
Elizabeth Chang, staff writer for the Washington Post, wrote in her Oct. 7, 2003 article "Tempest in a Glass: Synthetic Hormones in Milk Don't Speed Puberty, Say Experts":
"Could hormones meant to make cows give more milk lead to early puberty, as some parents fear? On its face, it sounds plausible enough. But government and pediatric health experts say there are no scientific data to back up such an assertion. For one thing, they say, rBGH [man-made bovine growth hormone] does not survive pasteurization. And even if it did, they add, it has absolutely no effect on human growth...
For years, pediatricians have viewed age 11 as the mean age of breast development... In 1997 a landmark analysis of 17,000 U.s. girls led by University of North Carolina professor Marcia Herman-Giddens showed that many American girls were beginning to show secondary sexual characteristics between ages 9 and 10... But the changes documented in Herman-Giddens's study cannot be attributed, even in part, to artificial bovine growth hormone for one important reason: The data for her study were collected in 1992 and 1993, before rBGH was available for dairy herds in the United States. Another problem with the rBGH and early puberty theory: Children today drink markedly less milk than they did a generation or two ago."