Identical Twins Vs. Fraternal Twins: What’s The Difference?
June 1, 2018 11:46
People have always been fascinated by twins; there’s been plenty of speculations and mystery around them. Besides, they can be so different.
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They are commonly called identical twins and fraternal twins. Scientifically, they are monozygotic and dizygotic twins, or homozygous and heterozygous twins, respectively. The first ones appear when two embryos are formed by division of one zygote. The fraternal twins develop from two or more egg cells fertilized by different spermatozoa.
How are identical twins formed?
Each woman is born with a certain set of egg cells. They mature during her life, more precisely, her reproductive age. At the first phase of the menstrual cycle (before ovulation), about 20 egg cells mature in the follicles of both ovaries. As usual, on the 7-9 day, most of them degenerate. And only 1 follicle in either ovary becomes dominant.