The IQ advantage of the heavier twin.
The monozygotic twin member with the larger birth weight later has a slight IQ advantage over the lighter co-twin. The question arises whether this is due to interconnected foetal circulations (which in extreme cases cause the twin transfusion syndrome). An attempt is made to clarify this hypothesis.
D001724:Birth Weight; D002657:Child Development; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007360:Intelligence; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D014427:Twins / Q000523:psychology*; D014430:Twins, Monozygotic / Q000523:psychology*