Nobel laureate David Baltimore of Caltech speaks to reporters at the National Academy of Sciences international summit on human gene editing, on Tuesday in Washington, D.C. Hundreds of scientists and ethicists from around the world debating how to deal with technology that makes it easy to edit the human genetic code. Susan Walsh/AP hide caption

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Scientists Debate How Far To Go In Editing Human Genes
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Powerful 'Gene Drive' Can Quickly Change An Entire Species
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Ken (left) and Henry were created using DNA plucked from a skin cell of Melvin, the beloved pet of Paula and Phillip Dupont of Lafayette, La. Edmund D. Fountain for NPR hide caption

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Cloning Your Dog, For A Mere $100,000
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Costs Of Slipshod Research Methods May Be In The Billions
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Cambrian Genomics says that what it calls a DNA printer is essentially a DNA sorter — it quickly spots and collects the desired, tailored stretch of DNA. Courtesy of Cambrian Genomics hide caption

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DNA 'Printing' A Big Boon To Research, But Some Raise Concerns
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Scientists Urge Temporary Moratorium On Human Genome Edits
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Along with sperm, the in vitro procedure adds fresh mitochondria extracted from less mature cells in the same woman's ovaries. The hope is to revitalize older eggs with these extra "batteries." But the FDA still wants proof that the technique works and is safe. Chris Nickels for NPR hide caption

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Fertility Clinic Courts Controversy With Treatment That Recharges Eggs
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The size of the brain of a chimpanzee (right) is considerably smaller than that of a human brain. Probably multiple stretches of DNA help determine that, geneticists say. Science Photo Library/Corbis hide caption

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Just A Bit Of DNA Helps Explain Humans' Big Brains
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Surgeons at Methodist University Hospital in Memphis prepare to transplant a liver in 2010. Karen Pulfer Focht/The Commercial Appeal/Landov hide caption

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Who Gets First Dibs On Transplanted Liver? Rules May Change
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U.S. Marine Sgt. Robert Scoggin gets a vaccination against smallpox in 2003 at Camp Pendleton in California — one of the final steps before deployment overseas. David McNew/Getty Images hide caption

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Keep Or Kill Last Lab Stocks Of Smallpox? Time To Decide, Says WHO
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Being able to insert the two man-made letters into DNA, alongside the usual four-letter alphabet, could teach old cells new tricks and lead to better drugs, researchers say. courtesy of Synthorx hide caption

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Chemists Expand Nature's Genetic Alphabet
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Botulism bacteria, or Clostridium botulinum, grow in poorly preserved canned foods, especially meat and fish. The microbe's toxin could be lethal as a bioweapon. Dr. Phil Luton/Science Photo Library/Corbis hide caption

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Who's Protecting Whom From Deadly Toxin?
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This mouse egg (top) is being injected with genetic material from an adult cell to ultimately create an embryo — and, eventually, embryonic stem cells. The process has been difficult to do with human cells. James King-Holmes/Science Source hide caption

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First Embryonic Stem Cells Cloned From A Man's Skin
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The research team used yeast chromosome No. 3 as the model for their biochemical stitchery. Pins and white diamonds in the illustration represent "designer changes" not found in the usual No. 3; yellow stretches represent deletions. Lucy Reading-Ikkanda hide caption

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Custom Chromo: First Yeast Chromosome Built From Scratch
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Erick Munoz stands by a photo of his wife, Marlise Munoz, at home in Fort Worth, Texas, on Jan. 3. She is being kept on life support in a local hospital against the family's wishes. Fort Worth Star-Telegram/MCT via Getty Images hide caption

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