Lavender And Tea Tree Oils May Cause Breast Growth In Boys: "A study published in this week's issue of the New England Journal of Medicine suggests that repeated topical use of products containing lavender oil and/or tea tree oil may cause prepubertal gynecomastia, a rare condition resulting in enlarged breast tissue in boys prior to puberty, and for which a cause is seldom identified.
Researchers at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health (NIH), confirmed in laboratory studies what a pediatric endocrinologist at the University of Colorado at Denver and Health Science Center's School of Medicine suspected after diagnosing three of his young male patients with prepubertal gynecomastia. The researchers found an association between the use of products containing these oils and the rare disorder, but cautioned more research is needed. At this point, the findings are only applicable to young males with unexplainable enlarged breasts who are regularly using products containing these essential oils."