"In response to requests filed earlier this year by the Public Patent Foundation (PUBPAT), the US Patent and Trademark Office (USPTO) will undertake a comprehensive review of four patents related to genetically modified crops held by Monsanto that the agricultural giant is using to harass, intimidate, sue - and in some cases literally bankrupt - American farmers. The crime these farmers are accused of is nothing more than saving seed from one year's crop to replant the following year, something farmers have done since the beginning of time. In its Orders granting the four requested reexaminations, the USPTO found that PUBPAT had submitted new evidence that raised "substantial questions of patentability" for every single claim of each of the four patents," quoting the Public Patent Foundation.
The Patents & related documents list.

This was highlighted in the film The Future of Food mentioned here previously & now available for purchase through Amazon.com.