Monozygotic, or identical, twins originate from one egg cell and one sperm cell, following an early division of the embyro. As such, monozygotic twins share the same genetic material, are of the same sex and physically very similar.
Dyzygotic twins (fraternal twins) come from the fertilization of two different egg cells, each one by a different sperm cell. In this way, fraternal twins can be of the same or different sexes, and physically look alike as do siblings from different pregnancies.
Read the full article on: Is having twins hereditary? What are the influencing factors? ( 49).
By Cristina Mestre Ferrer B.Sc., M.Sc. (embryologist), Michelle Lorraine Embleton B.Sc. Ph.D. (biochemist), Silvia Azaña Gutiérrez B.Sc., M.Sc. (embryologist) and Zaira Salvador B.Sc., M.Sc. (embryologist).
Last Update: 06/28/2022
