Preschool Puberty, and a Search for the Causes looks at the various household products that mimic hormones:
In a 1998 paper in the journal Clinical Pediatrics, Dr. Chandra Tiwary, the former chief of pediatric endocrinology at Brook Army Medical Center in Texas, reported an outbreak of early breast development in four young African-American girls who used shampoos that contained estrogen and placental extract. The early puberty reversed once the shampoo was stopped.In the tradition of previous physicians who deliberately exposed themselves to possible pathogens, Dr. Tiwary tried the shampoos on himself. He carefully measured his own levels of various male and female sex hormones to establish his baseline, used the shampoos for a few days, then repeated the tests.
While Dr. Tiwary is quick to admit that his unpublished findings must be interpreted with great caution, some of his sex hormone levels changed by almost 40 percent after he used the shampoos. In some cases, substances other than sex steroids may also disrupt normal sexual development. In Boston at the annual Endocrine Society meeting in June, Clifford Bloch of the University of Colorado School of Medicine presented several cases of young men who had developed marked breast enlargement from using shampoos containing lavender and tea tree oils, which are widely used essential oil additives that present no problem for adults.
Dr. Bloch collaborated with scientists at the National Institute of Environmental Health Sciences in North Carolina to test the oils on human breast cells grown in test tubes. Lavender and tea tree oil had the same effect on the cells as estrogen.