Fortunately, the vast majority of men who work with potentially risky chemicals and substances do not father children with birth defects, nor do their partners have a higher-than-normal risk of pregnancy complications. However, a small number of industrial, chemical, and environmental substances may affect the male reproductive system, resulting in low sperm count and infertility, miscarriage, and other problems.
In the 1970s and 1980s, research showed that miscarriage and infertility could result from a father's exposure to vinyl chloride, which is widely used in the electronics industry. Since then, studies have suggested that a man's exposure to metals (such as lead and mercury), to chemicals used in rubber and plastic manufacturing, and to certain industrial solvents before and around the time of conception may also increase the risk of miscarriage. In most cases, these men were more likely to produce abnormal sperm, which resulted in unviable embryos.
Recent studies suggest that some of the most risky chemicals are industrial solvents, such as benzene and ethylene glycol ethers. One study found that men who were exposed on the job to ethylene glycol ethers were more than twice as likely as unexposed men to be infertile. The people likeliest to encounter these solvents include dry cleaners, printers, textile workers, computer-chip factory workers, pesticide sprayers, and anyone who works with paints, varnishes, or paint thinners. Pesticides may also pose other risks. One study suggested that male applicators of particular pesticides may be at increased risk of fathering a child with a birth defect or learning and behavioral disabilities.
That said, expectant fathers and men thinking about fatherhood should take all practical steps to protect themselves (and their future children) from toxins in their workplace. Keep in mind that a person can take these chemicals into the body by breathing them in, ingesting them in food or drink, or absorbing them through the skin. Workers should always wear recommended protective clothing and equipment, such as a mask and gloves. Also, it's vital that anyone who works around these chemicals take their meals outside any chemically contaminated work area.
Men who are exposed to lead, such as painters or those working in smelters, auto repair shops, battery manufacturing plants, or certain types of construction, should do everything they can to avoid bringing lead dust into their home on their clothes and shoes. When a pregnant woman is exposed to high levels of lead, it can contribute to miscarriage, preterm delivery, low birth weight, and developmental delays in the infant. Dad should change and shower at work, and if possible, launder contaminated clothing there. If this isn't possible, he should wash work clothes at home separately from the rest of the family's clothes.