Pin On Twins
Identical ( monozygotic) twins are always of the same sex because they form from a single zygote (fertilized egg) that contains either male (XY) or female (XX) sex chromosomes 2 Fraternal twins can be either two girls, two boys, or one ofIdentical twins share the same gender—boyboy, girlgirl Boygirl twins are always fraternal A boygirl pair may be identical with a rare genetic mutation, but this brother and sister are like
