In the United States and Japan, there has been a significant decline in the birth of baby boys. What does this have to do with testicular cancer? Well, there's a theory of testicular dysgenesis, which means that there is something on the Y chromosome that is transmitted to boys that is affecting their overall health, and it may affect whether or not a boy sperm works to fertilize an egg.
Something is affecting fathers' ability to make baby boys, which may also be affecting the ability of the boys that are conceived to become fathers. It may be affecting sperm count, which is declining. It may also be affecting development of testicular cancer, which peaks in young men in their 20s. And these things are likely to be related to early life exposures to hormone-mimicking chemicals.Pesticides, alcohol, lead and solvents have all been shown in occupational studies to reduce the ability of men to father boys and to increase the risk of birth defects in the babies that they have, including cancer. There's recently been a report from the Arctic Assessment of many more girls than boys being born. If something is affecting such an exquisitely sensitive part of human biology, then what else is it doing to us?"
—Dr. Devra Davis, professor of epidemiology at the University of Pittsburgh Graduate School of Public Health and author or The Secret History of the War on Cancer (2007, Basic Books) in an October 2007 interview by Salon