The scientific principles behind the birth of twins
With the development of modern medical technology, more and more couples choose to use artificial reproductive technology to realize their fertility wishes. Among them, giving birth to twins, a boy and a boy, is a rare but highly-concerned phenomenon. So, how are twins born? What is the scientific principle hidden behind it? This article will elaborate on the scientific principles of giving birth to twins from four aspects.
1. The issue of gender ratio
The gender combination of twins is generally one male and one female, that is, one boy and one girl are born in one birth. This is mainly determined by the imbalance of the sex ratio of human sperm. Research shows that male sperm has a higher proportion of Y chromosomes and a lower proportion of X chromosomes. Therefore, if a woman is fertilized during the ovulation period, she may give birth to a girl, and fertilization three days before the ovulation date may result in a girl. A boy will be born. After the eggs undergo in vitro fertilization, doctors can screen out the sperm with a high probability of appearing in the same gender, thereby achieving the birth of twins.
2. The occurrence of multiple pregnancy
Except for a single egg that splits into two embryos after fertilization to form a parasitic fetus, not all twins or multiples are determined by size, shape, or random factors. In fact, in addition to the situation where the egg divides early after fertilization and later stops dividing and merges into one embryo, multiple fertilizations of eggs and sperm may also lead to the occurrence of twins. This process is called multiple pregnancy.
3. Polyzygotic twins and embryo matching technology
Polyzygotic twins occur when a woman releases two or more eggs at the same time during one ovulation and they are fertilized separately. Polyzygotic twins are more common than monozygotic twins because as a woman ages, most of the eggs in her body fail to successfully fertilize or divide into embryos. Moreover, in artificial reproductive technology, embryo matching technology can achieve the purpose of twins of different genders by coupling different embryos together.
4. Family genetic factors and environmental factors
In addition to the special circumstances mentioned above, the birth of twins may also be affected by family genetic factors and environmental factors. In some families, there may be certain genetic mutations that cause the children\’s germ cells to have different sex ratios during fertilization. Environmental factors, such as eggs and sperm being affected by external factors (such as radiation, chemical pollution, etc.), may also cause changes in the sex ratio of eggs and sperm, resulting in twins.
To sum up, the birth of twins is determined by many factors. In addition to the help of medical technology, one\’s own genetics and external environment may also affect the occurrence of twins. In this regard, people need to understand more and gradually explore its scientific principles.
