Something a pregnant woman is exposed to may alter not just her children, but also her grandchildren – and possibly even subsequent generations.

This is how the “germ line” hypothesis works: Cells in what is called a “germ line” form eggs in the female fetus and precursors to sperm in the male fetus. The germ line establishes an unbroken link from generation to generation. But when a pregnant woman is exposed to chemicals, the germ line may be altered. That would mean that eggs developing in the fetus – the future third generation – could be changed, leading to abnormalities or disease. Also, the disrupted programming in how genes are turned on and off – the very genes that instruct cell growth and function – may be passed on to more descendants. Read…