U.S. and Chinese scientists today reported a human pregnancy with fetuses resulting from three genetic parents. The technique used is nuclear transfer, description is below.
An excerpt from New Scientist:
"The work in China was led by John Zhang and colleagues at the Sun Yat-Sen University of Medical Science in Guangzhou, China, and presented at the American Society for Reproductive Medicine's meeting in San Antonio, Texas, US. They removed the fertilised nuclei (pronuclei) from one set of eggs and implanted them into another set of emptied eggs.
The eggs produced by this nuclear transfer had genetic material from three people - nuclear DNA from the man and woman who created the pronuclei and mitochondrial DNA from the woman donating the second egg."
I should note that children with three genetic parents have actually been born. That fertility treatment work was revealed back in 2001.