- Shinryo N. Shinagawa, MD. Emeritus Professor of Hirosaki University School of Medicine 32-3 Fujimicho Hirosaki, Japan, 036-8223 E-mail: email@example.com
After a short introduction of population policy in modern Japan, especially in postwar decades, six topics will be presented. They are:
Statistics on sex ratio of neonates in postwar Japan
Traditional attitude of Japanese people on the sex of neonates
A short history of sex diagnosis of fetus in utero in Japan
A short history of preconceptional sex selection in Japan with special attention to a heat discussion triggered by a method developed in a famous medical school in Tokyo and its aftermath
Ethical guidelines on antenatal sex selection, especially by preconceptional sperm selection method adopted by Japan Medical Association and by Japan Society of Obstetrics and Gynecology mainly done on the indications of antenatal sex selection. Average public opinion on this issue in today's Japan will also be discussed.
As probably many friends know it, Japanese Government of Tokugawa Shogunate ever took an isolation policy and closed the door against most foreign countries from 1639 to 1858. In isolation policy period of more than 200 years, population in Japan was stabilized in a level of around 35 million in spite of Japan had no chance of immigration to such countries as Hawaii, United States, Canada, Mexico and so on. Furthermore, Japan had no history of international war and domestic conflict which easily resulted to massacre and decrease in population.
Why was the population in Japan so stabilized during isolation policy years? To this question there exist many answers. One of them, it is my own, is the popularization of induced abortion and of infanticide especially among poor peasants.
After the opening of doors against Euro-American countries in 1860's, new leaders of Japan noticed an important fact. That is in most Euro-American countries induced abortion and infanticide were all immoral and illegal, and so in early 1868 Japanese new government enacted a law on midwifery regulation, and Japan became probably the first Non-Christian country, which prohibited the induced abortion and infanticide except in cases of medical indications. Indeed, the first health care law in Japan was Midwifery Regulation Law in 1868. This abortion-prohibiting policy continued very strictly in Japan to the end of the World War II.
However, soon after the end of World War II, more exactly in 1948, a law, which greatly liberated the induced abortion, passed the Diet in the name of maternal welfare and mother(hood)-protection. This is Eugenic-Mother(hood)-Protection Law, and since 1948 Japan became one of countries legal abortion available. In past revision was done on the indications of induced abortion. In other words, in Japanese abortion law, there exist only maternal indications but no fetal indications. And in practice, therefore, almost nothing has been legalized in Japan on embryo/fetus, and on recent issues relating to modern ART (artificial reproductive technologies). Only heat endless discussion is continuing.
Traditionally, it has been widely said and believed that male/female ratio, boy/girl ratio or sex ratio at birth is around 105/100. However, many recent works are reporting that some changing is occurring in sex ratio. Many reports from Asian countries are reporting an increase in induced abortion when a prenatal diagnosis of a girl was given. On the contrary, in western countries not a few papers are reporting a slight decrease in sex ratio, especially in Atlantic Region of Canada, probably due to unknown factors in environmental changing.
However, the answer is "No" as you can see in the next Table 1. Although many discussions have been done on prenatal sex selection and a variety of prenatal sex diagnosis were popularized in Japan especially since 1980s, almost nothing seems to be occurring as a whole in Japan.
Year Male (x 1,000) Female (x 1,000) Sex ratio
1951 1,094 1,043 1,048
1960 824 781 1,055
1970 1,000 933 1,071
1980 811 765 1,061
1990 626 594 1,053
1999 617 585 1,054
Japan is traditionally one of the countries of predominance of man over woman, and in most families and couples the birth of a boy is more welcomed than of a girl very usually because social handicaps were very common in Japanese society. For example, before 1945 no girl could study in national university, and no woman could occupy a higher social position such as member of parliament, member of cabinet, president of large company, professor of national university and so on.
However, the situation in Japanese community is slowly but very steadily and greatly changing since 1945. Today in Japanese Cabinet, 4 seats of 18 ministers are occupied by ladies, and in national universities boys/girls ratio is around 50/50.
As far as I know and remember, the first medical method used in prenatal sex diagnosis in utero was X-ray fetography and/or amniography by the use of radiopaque iodine medium since 1930s. But the findings and diagnosis obtained were not so exact and correct. And a variety of hazardous influences of radioactivity on fetus in utero experienced in Hiroshima and Nagasaki were so great and terrible. From these two reasons, X-ray fetography and/or amniography had been abandoned in post-war Japan.
The second methods used in prenatal sex diagnosis were done using cytology. Whether sex chromatin can be found or not in epithelial cells floating in aspirated amniotic fluid, in biopsied chorionic villi of the placenta, and in leukocytes obtained from umbilical cord blood vessel blood. But all these methods were not so widely used because risks of induction of labor, abortion, premature delivery, maternal bleeding, and unacceptable injuries of the fetus or of the mother could not be ignored.
The third method debuted and most widely spread for the diagnosis of fetal sex is ultrasonography. By this method, reliable figure can be obtained very surely without any noticeable risks when gestation exceeds the 20th or 22nd week. Only one disadvantage of ultrasonography in the diagnosis of fetal sex is a practical fact that induced abortion in later than 20th or 22nd week is prohibited legally or by guideline of medical association in many countries..
Many trials have been done in Japan on preconceptional sex selection of the baby aiming to obtain a baby of wanted sex without to obtain a reliable method. However, in May of 1986 a shocking report was done by the researchers of Keio University in Tokyo. They reported a method called the Percoll Method, and announced that they have succeeded in separating layers of sperm where boys are easily conceived and layers of sperm where girls are easily conceived.
Immediately, the Japanese mass media handled this in a big way. And opinions for and against this preconceptional sex selection came up against each other. People approving expressed the following: It would help to prevent the birth of children with severe sex-linked recessive genetic disorders. It could benefit those who were hoping for a specific sex in their next child; There is a possibility, that it might control population increase.
There were more than a few who opposed preconceptional sex selection for the following reasons: Patients and doctors should not go so far as to interfere with sex of a baby yet to be born; It would mean discrimination against people who have severe sex linked recessive genetic disorders; It would cause even greater sex discrimination; There is a possibility that this procedure could be abused by militarists.
This problem was taken up by the Ethical Committee of the Japan Society of Obstetrics and Gynecology (JSOG). And at the almost same time, the Ethical Committee of the Japan Medical Association took up the problem. These two ethical committees came to about the same conclusion in September of 1986, and announced that this procedure should be adopted only to prevent the conception of conceptuses with severe sex linked recessive genetic disorders. The details of these Ethical Committees were as follows: Preconceptional sex selection by the use of Percoll Method may be practiced only by physicians with advanced training and knowledge of reproductive medicine; Members who wish to practice this method must register with the Society in advance, using the registration form designated for this purpose by the Society; The practicing physician must fully explain the nature of the method and the expected outcome to the subjects beforehand, and must obtain and keep on file statements of informed consent from subject couples.
But in June of 1994, Ethical Committee of JSOG made another announcement and prohibited Percoll method because of its possible hazardous effect on sperm and on fetus.
Since April of 1994, another discussion is in progress in Japan. That is on the prevention of birth of a boy with progressive muscular dystrophy. Doctors of Kagoshima Medical School (KMS) planned to judge the sex of in vitro fertilized ovum of a wife fertilized with her husband's sperm because this couple have a child with Duchene muscular dystrophy. Ethical Committee of KMS accepted it. However, Ethical Committee of JSOG rejected it. JSOG says that instead of postconceptional sex diagnosis, gene anomaly should be studied primarily. Gene diagnosis should be the first choice. This is our opinion since 1998, JSOG said.
Finally, I would like to talk about two serious problems relating to demography, population and perinatology in Japan. The first, this is the most serious, is a continuous decrease in birth rate. Birth rate (per 1,000 population) in 1999 was only 9.8. This value is less than one third or one half of the past. The second is a gradual increase in rate of low birth weight infants. Modern ART, especially in vitro fertilization, is accelerating this tendency. This is, both in finance and in man-power, one of the most serious problems in maternal-child-health care in today's Japan.
Japan is one of the countries with the longest life-expectancy and with the lowest perinatal and infant mortality rates, and almost no change is occurring in sex ratio of neonates. But the future of Japan is not so bright. Thank you very much for your attention and advice.