Everyone must have seen people who look exactly the same. Generally, people who look exactly the same are mostly twins. Of course, twins are also divided into monozygotic twins and dizygotic twins. Homozygotic twins may have similar appearances, but dizygotic twins may have different appearances. So which is less likely, monozygotic or dizygotic?
Compared to the other two, the probability of having a different egg is lower because most women only release one egg during ovulation. If two sperm enter the egg at the same time during ovulation, a fertilized egg will be formed. If the fertilized egg carries the y chromosome, the developed embryo will be male.
If the chromosome carried is x and combines with the egg, the developed embryo is female. If two sperm carry the same chromosome, the twins born will also be of the same gender, otherwise they will be of different genders. Heterozygotic twins are fertilized eggs formed when two or even multiple men combine with sperm during ovulation in females.
Under normal circumstances, this probability is very small, but if some drugs are used, there is a high probability that many women will have twins. At present, most twins in China are identical twins, and some black people have a higher chance of having fraternal twins. The probability of having identical twins or fraternal twins is much lower than the probability of having a single child.
