According to doctors, a Wisconsin couple's birth of identical triplets are a rare 15 million to one.

Matthew and Christina Rowe had identical twin girls two years ago and now are adding identical triplet boys to the mix - an occurance that is extremely rare without the use of fertility drugs.

The mother of five says other than sleep deprivation, the hardest part is telling the boys apart. Christina Rowe says they're keeping tracking of the boys with the help of a marker on their tiny feet.