1. Lost boys: Studies on births from the U.S., Japan, and Canada have found a drop in the percentage of boys born compared with girls. The reason isn't known.
2. Declining harvest: Men in farm country can be half as prolific when it comes to making sperm as their city counterparts, raising the possibility that pesticides undermine male fertility.
3. Downsizing: It's disputed by chemical companies, but some researchers say they have found an everyday plastic compound - phthalates - that feminizes baby boys, causing penises and other reproductive organs to be smaller.
4. Hormones not so raging: If you're a middle-aged man, you're likely to be less virile than your father because you make less testosterone. In recent decades, the decline has averaged about 1 per cent a year. If it continues over another generation or two, the consequences could be dire.
5. Equipment failure: Rates of testicular cancer, hypospadias and other genital abnormalities have soared over recent decades, rising by more than 50 per cent each.
Mittelstaedt then lists the four chemicals that are causing the biggest concern: Bisphenol A, Phthalates, Polybrominated diphenylethers (PBDE). Polychlorinated biphenyls (PCB)