Answer: I think what you are refering to is nicknamed the "terminator" technology, still in the research stages. The purpose of this research is to create seeds--sometimes called "suicide seeds"--for major crop plants that are engineered to be sterile. This means that farmers won't be able to save seed from these crops to plant the next season. While this won't have much effect on U.S. farmers, who for the most part buy new seeds each year, it will affect farmers in third-world countries who routinely save seed from one year to the next. If these "terminator" seeds become the norm, to the exclusion of other, non-terminator types, then these farmers may be forced to buy new seed each year--an expense which many cannot afford.
To learn more about both sides of the debate, search the web using the keywords "terminator" and "seed". Below is a site that sums up the "terminator" research and debate.
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