BBC News | More evidence essential oils 'make male breasts develop' BBC News A suspected link between abnormal breast growth in young boys and the use of lavender and tea tree oils has been given new weight, after a study found eight chemicals contained in the oils interfere with hormones. Gynaecomastia is rare, and there is ... Chemicals in lavender and tea tree oil appear to be hormone disruptors Two common essential oils contain endocrine-disrupting chemicals |