Photographs showed the facial differences between twins, one of whom allegedly smoked and tanned for 16 years while the other ...

Find out everything you've always wanted to know about identical twins – from how they form to what makes them unique.

Even fewer cases of semi-identical (sesquizygotic) twins have been reported in medical literature. In these cases, a single egg is fertilized by two sperm. The egg then divides and develops into ...

It is the first time semi-identical twins have been identified during pregnancy. The first-time mother was 28 at the time and had conceived naturally, doctors said. The case is being reported on ...

Identical twins are not as identical as previously assumed, according to a study published today (January 7) in Nature Genetics. Rather than having exactly the same DNA sequences, twins start ...

MZ twins are generally assumed to be genetically identical, although some genetic and epigenetic differences have now been described. A newly published finding that phenotypically concordant as ...