1. Theoretical basis for the ratio of male and female test tube babies of the second generation
Can the male female ratio of second-generation IVF babies be predicted? First of all, we need to understand what factors affect the male female ratio of second-generation IVF. This ratio is regulated by the genetic mechanism of the Y chromosome, the child's sex determining factor. Male germ cells carry Y chromosomes, while female germ cells carry X chromosomes. When the Y chromosome in the sperm combines with the X chromosome in the egg, a boy will be born; When the X chromosome in the sperm combines with the X chromosome in the egg, a girl will be born. Therefore, the prediction of the ratio of male to female in the second generation of test tube infants is essentially to predict the probability of Y chromosome and X chromosome combination.
In scientific research, it is generally believed that the number of Y chromosomes carried by sperm is 50%, and the number of X chromosomes carried by sperm is 50%. Therefore, theoretically, the ratio of male to female of the second-generation IVF should be 1:1. However, in practice, some factors may lead to the deviation of the male female ratio of second-generation IVF babies.
2. Factors affecting the ratio of male and female test tube babies of the second generation
Scientific research has found that the following factors may affect the male female ratio of second-generation IVF babies:
2.1 Genetic inheritance of parents
The genetic inheritance of parents may affect the male female ratio of the second generation IVF. Early studies have shown that some parents' gene types may cause them to carry more Y chromosomes or X chromosomes, thus affecting the ratio of male to female test tube babies of the second generation.
A study conducted in a hospital found that when one of the parents suffers from chromosome related diseases, the proportion of the second generation of IVF boys is higher. This suggests that chromosomal abnormalities may be related to the deviation of the male female ratio.
However, the above research results have not been widely verified, so the influence of parents' genetic inheritance on the sex ratio of the second generation IVF still needs further research.
2.2 Embryo selection technology
Embryo selection technology refers to the technology of screening out gender before IVF through early embryo diagnosis. This technology can help parents choose the gender they want their children to be, so as to artificially affect the male female ratio of second-generation IVF babies.
In some countries and regions, embryo selection technology is widely used in sex selection of second-generation IVF. For example, in a well-known hospital in China, there have been many cases of successful selection of boys through embryo selection technology.
The application of embryo selection technology has made a significant change in the male female ratio of the second generation of IVF, but this method is artificial selection of gender, which is not consistent with the natural male female ratio.
2.3 Embryo culture conditions before IVF transplantation
Before the second generation IVF transfer, embryos need to be developed in culture medium. The study found that the composition of the embryo culture medium may have a certain impact on the male female ratio of the second generation of test tube babies.
Some studies have shown that embryo culture medium containing high salinity or low amino acid concentration may lead to better survival of Y chromosome sperm, thus increasing the proportion of boys; The embryo culture medium containing low salinity or high amino acid concentration may be biased towards the production of girls.
It is worth noting that these research results have not been widely verified in clinical practice, so the influence of embryo culture medium on the male female ratio of second-generation test tube infants needs further discussion.
3. Is the male female ratio of second-generation IVF predictable
According to the current scientific research, we can draw a preliminary conclusion that the male female ratio of the second generation of IVF babies is predictable to some extent.
By detecting the genetic characteristics of parents, applying embryo selection technology and controlling the composition of embryo culture medium, we can carry out a series of operations to try to affect the male female ratio of second-generation IVF. However, these methods are not 100% accurate, nor can they completely change the natural ratio of men and women.
Therefore, although there are some factors that affect the male female ratio of the second generation of test tube babies, we still cannot make an absolutely accurate prediction of the male female ratio of the second generation of test tube babies due to the imperfect scientific research.
4. Summary
In general, the prediction of the proportion of male and female test tube babies in the second generation is related to multiple factors. Parents' genetic inheritance, embryo selection technology and embryo culture medium conditions may affect the male female ratio. However, due to the imperfection of scientific research, we can not make an absolutely accurate prediction of the male female ratio of the second generation of IVF at present. Future research still needs to be further explored to increase the understanding of the influencing factors of the male female ratio of second-generation IVF infants and provide more accurate prediction methods.
