The story posted at Breitbart.com details the work done to genetically alter common onions to eliminate the tear-causing enzymes.

New Zealand researchers used "gene-slicing" techniques to modify the onion's genetic makeup, turning off the gene which causes tears. Japanese researchers had identified the gene in 2002.

The report quotes one researcher's explanation of the process: "We had the ability to insert DNA into onions, using gene-silencing technology developed by Australian scientists. The technology creates a sequence that switches off the tear-inducing gene in the onion so it doesn't produce the enzyme. So when you slice the vegetable, it doesn't produce tears."

The hope is that besides being tear-free, the onions will also have an improved flavor: "We anticipate that the health and flavour profiles will actually be enhanced by what we've done. What we're hoping is that we'll essentially have a lot of the nice, sweet aromas associated with onions without that associated bitter, pungent, tear-producing factor."

The break-through was featured in an article in Onion World, the magazine of onion growers.

It will likely be 10 to 15 years before tearless onions are available for consumer use.