Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be?

YOU ARE READING
Logic Brain Teasers and Trick Questions
RandomTest friends, family, and even yourself in these brain teasers and trick questions! Comment and vote for more updates, answers or debates. :P
Twins
Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be?