Most people who give it serious thought know GM foods are a crap-shoot -- not enough research to be sure they are safe in the long run. And then I ran across this new (new to me) worry in the Organic Consumers Association newsletter #226 (May 28, 2010):
Genetically Modified Foods Could Cause Long-Term Sterility
"We failed to get cubs from these pairs, which were fed with GM foodstuffs. It was proved that these pairs lost their ability to give birth to their cubs."
This quote is Dr. Alexei Surov, a Russian biologist describing the results of a study of hamsters fed genetically modified soy for two years over three generations. By the third generation, most the hamsters lost the ability to have babies. The pups who were born suffered slower growth and a high mortality rate.
You can track down the whole story via the Organic Consumers Association.