A number of scientific studies suggest that sperm quality has decreased substantially in the past 50-80 years. For instance, a recent study indicates that, on average, the sperm count per ml is 52%, and the total amount of ejaculate is 59%.
These studies suggest that the decreased is more noticeable in industrialized countries.
Although the causes of this phenomenon are varied, it seems that the main reason can be found in the environment, and are endocrine disruptors. I am talking about chemical substances that simulate the effect of hormones by sending confusing signals to the organism, causing different dysfunctions, including a reduction in the sperm production process.
Endocrine disruptors are commonly found in consumer products, such as plastic, personal hygiene products, cleaning products, air fresheners… Also, many are present in foods.
Some examples of endocrine disruptors are dichlorodiphenyltrichloroethane (DDT), which was prohibited long time ago, bisphenol A, phthalate, styrene, certain solvents, resorcinol, etc.