(CNN) You've probably heard of identical and fraternal twins, but a report published Thursday says there's a third kind -- sesquizygous twins or "semi-identical." They share 100% of their DNA. They share 50% of their DNA. But "semi-identical" twins are so rare, experts say they have only identified two cases -- ever. Right along that DNA-sharing spectrum, "semi-identical" twins share anywhere from 50% to 100% of their genomes, researchers say.

Source: CNN March 01, 2019 03:22 UTC