Lower levels of testosterone are linked to exposure to an endocrine-disrupting chemical exposure, a new study suggests. The new study, published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism, shows that men, women, and children with exposure to increased levels of phthalates, endocrine-disrupting chemicals in plastics and certain personal care products, have lower levels of testosterone in the blood when compared with individuals with decreased chemical exposure.

Testosterone, the primary sex hormone in men, plays an important role in both sexes, such as physical growth and strength, brain function, bone density and cardiovascular health. Over the past 50 years, research has indicated a decline in testosterone in men and an increase in related health conditions, such as lowered semen quality in men and genital malformations among newborn boys.

Study author John D. Meeker, MS, ScD, from the University of Michigan School of Public Health in Ann Arbor, MI, said in a statement, “We found evidence reduced levels of circulating testosterone were associated with increased phthalate exposure in several key populations, including boys ages 6-12, and men and women ages 40-60.” He continued, “This may have important public health implications, since low testosterone levels in young boys can negatively impact reproductive development, and in middle age can impair sexual function, libido, energy, cognitive function and bone health in men and women.”

According to WebMD, many men start to experience a gradual decline in testosterone after the age of 30.