@CNN: You’ve probably heard of identical and fraternal twins. But a new report says there’s a third kind — sesquizygous or “semi-identical” twins, so rare that only two cases have ever been identified https://t.co/kM2woWgY1H

You've probably heard of identical and fraternal twins. But a new report says there's a third kind — sesquizygous or "semi-identical" twins, so rare that only two cases have ever been identified https://t.co/kM2woWgY1H

— CNN (@CNN) March 1, 2019