All of which makes them valuable to study. Twins share everything from their in-utero environment and parents to birthdate and the classroom setting. One unusual case study involved two-and-a-half ...

All of which makes them valuable to study. Twins share everything from their in-utero environment and parents to birthdate and the classroom setting. One unusual case study involved two-and-a-half ...

Against all odds, a mother in Hanoi gave birth to twins five weeks apart, with the older twin born prematurely at 26 weeks ...