Advocating genetic counseling can avoid the birth of children with genetic diseases;
A. it is forbidden to marry close relatives: the reason is that close relatives are more likely to have the same recessive genetic disease-causing gene, and children born to close relatives are more likely to suffer from genetic diseases. For example, the incidence of single-gene recessive genetic diseases of children born to close relatives is 7.8 ~ 62.5 times that of non-close relatives; The probability of congenital malformation and stillbirth is 3 ~ 4 times higher than that of the general population. Children's mental decline, suffering from many congenital diseases, such as congenital stupidity, is very harmful. The effective measures to prevent genetic diseases are to prohibit consanguineous marriage and make mistakes.
B, prenatal diagnosis, can monitor the baby's development, according to the fetal position, development, whether there is an umbilical cord around the neck. Choosing scientific delivery measures and making good prenatal preparations can avoid the harm to fetal position and umbilical cord around the neck. B correct;
C. Contents and steps of genetic counseling: (1) The doctor conducts a physical examination on the client, understands the family history, and makes a diagnosis on whether he has some genetic disease.
(2) Analyze the transmission mode of genetic diseases.
(3) Calculate the recurrence risk rate of offspring.
(4) Put forward countermeasures and suggestions for termination of pregnancy and prenatal diagnosis. Mistakes;
D. Premarital check-up plays an important role in the health of both men and women, prenatal and postnatal care and the development of the next generation. It is the key to reduce hereditary diseases, reduce physical defects and unhealthy factors transmitted to future generations, and is an important measure to achieve eugenics for future generations. D error.
So choose: B.