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Parent-Child Relationships and DNA Analysis
- Should Legal Paternity be Determined According to Blood Ties?

Masayuki Tanamura
Professor, Faculty of Law, Waseda University

Although Japan has a tradition of emphasizing blood ties and the idea that “blood is thicker than water”, there are also those who believe that weight should be placed on nurture and that children’s foster parents are dearer than their biological parents. Both ideas have their merits. However, advances in DNA analysis and medical technology have led to significant changes in the relationships between married couples and their children. In a high-profile case in December 2013, for example, the 16-year-old son of a divorced show business couple was proven by DNA analysis not to be the father’s biological son and, after talks between the couples’ respective lawyers, the maternal grandmother was awarded custody of the boy. In November of the same year, the results of DNA analysis were also applied in a lawsuit triggered by an inheritance dispute and filed by a 60-year-old Tokyo man against a maternity hospital, the DNA evidence revealing a mix-up between newborn babies just after birth. In another case of a couple in western Japan in their 30s, the wife, who had borne another man’s child while her husband was living away from home on business, filed a lawsuit seeking confirmation that her husband was not the child’s father. At the first trial in April 2012 the results of DNA analysis were given most weight, and at the second trial in November 2012 consideration was given to the fact that the boy was very young, living with his mother’s partner, and calling him “daddy”, upon which the court found there was a lack of a paternal relationship with the husband.

Incidentally, the provisions of Japan’s Civil Code place faith in the morals of marriage and medical statistics so that when a married woman becomes pregnant her husband is assumed to be the father of the child. In principle, however, paternity can never be contested unless the husband has acknowledged the child to be his or requests a trial to deny legitimacy within one year of his knowing about the birth, even supposing that there is actually no blood relationship. The reason for setting such a strict rule is to preserve domestic harmony and the couple’s privacy as well as to establish the child’s status at an early stage. When a child is born outside marriage, the only way is voluntary notification of acknowledgement by the father or a court acknowledgment. There are also various restrictions under the Civil Code, such as a man who has given notification of acknowledgement being unable to reverse his notification, the need for maternal consent in order to acknowledge an unborn child or the consent of the child himself or herself in order to acknowledge a grown-up child, and the ability for an interested party including the child to request an annulment of an acknowledgment. These legal mechanisms show that legal paternity is not necessarily determined by inherited blood.

The framework of the Civil Code originally goes back 115 years or more to a patriarchal family system and an inheritance system under which the eldest son inherited the property of the family. In those days, paramount importance was attached not to personal happiness but to the survival and continuation of the patrimonial family as a group of descendants of the male line. Furthermore, there were few divorces or remarriages, let alone scientific methods of testing paternity such as the analysis of blood type or DNA. Nor were there assisted reproductive technologies such as artificial insemination, in vitro fertilization, surrogate conception, or postmortem gestation. And of course the level of medical care was insufficient to save extremely premature infants weighing 500 grams or less. Nowadays, in contrast, DNA analysis is not only for scientifically investigating crimes and identifying the true culprits, it is also an assessment method that can reveal paternity with almost 100% certainty. And, because someone’s DNA sequence can be found using a very small sample of their oral mucus membrane, hair with its root, blood, etc., many private operators have begun to emerge. According to the Ministry of Economy, Trade and Industry, the number of businesses in Japan providing genetic testing services such as DNA analysis more than doubled from 340 in 2009 to 740 in 2012. As for DNA test charges, most cost from tens of thousands of yen up to a hundred thousand yen or more, although some operators will now charge fees as low as ten thousand yen or so if the clients apply online and can simply collect samples themselves and post them. There have, however, been cases of samples being sent to overseas DNA testing companies who misread the data results and made incorrect judgments, or of retests being required due to sloppy testing.

Against this background, in December 2013 the Supreme Court made a series of judgments on legal paternity. One case related to a man who had changed his sex due to a gender identity disorder and his wife who underwent AID (artificial insemination by donor) and gave birth to a child. The paternity of the husband, formerly a woman, had not been legally recognized at the first and second trials because he lacked the ability to reproduce so no genetic relationship existed with the child, but the Supreme Court overturned this judgment and ruled that legal paternity should be recognized because, under Article 772 of the Civil Code, a child borne by a wife is assumed to be the child of her husband. The second case in January 2014 involved a man married to a Filipino woman who had acknowledged his wife’s baby girl as his own even though he knew she was fathered by another man before their marriage. When the couple then separated, he argued for an annulment of his acknowledgement of paternity of the baby girl. The Supreme Court ruled that someone who has submitted deliberately false notification of acknowledgement is allowed to demand an annulment of that acknowledgement.

Even in cases of gender identity disorder or of permitting the annulment of acknowledgement, judges’ decisions have been somewhat swayed by whether to attach weight to natural blood ties or to consider the livelihood and welfare of the child more. Families have taken on increasingly diverse forms accompanying big changes to society and the family, while great strides have been made in the scientific assessment of paternity by DNA analysis. On the other hand, considering whether legal paternity should be determined according to natural blood ties or by placing weight on a child’s living circumstances, parental bonds, and happiness, does DNA analysis need to be somewhat limited? This series of cases illustrates that we are in an era in which the fundamental questions about the meanings of parent-child relationships and families are being addressed.

Masayuki Tanamura
Professor, Faculty of Law, Waseda University

Professor Tanamura graduated from the School of Law, Waseda University, and withdrew from the Doctoral Program, Graduate School of Law, Waseda University after completing the required course work. He served as professor on the Faculty of Law, Aoyama Gakuin University before taking up his current position as professor on the Faculty of Law, Waseda University. He is also a board member of the Japan Society for Socio-Legal Studies on Family Issues; a board member of the Association of Religious Law; a board member of the Japan Association of Gender and Law; an associate member of the Science Council of Japan; a member of the National Institution for Academic Degrees and University Evaluation’s Committee for Certified Evaluation and Accreditation of Law Schools; a councilor and mediator for the Tokyo Family Court; and an attorney.

[Major Publications]
Jurisprudence on Marriage [Kekkon no Houritsu-gaku], Second Edition (Yuhikaku, 2006); Legal Consultation for Husband and Wife [Fufu no Houritsu Sodan], Second Edition (co-authored and co-edited, Yuhikaku, 2010); Civil Law 7: Family and Inheritance [Minpou 7: Shinzoku, Sozoku], Second Edition (Yuhikaku, 2010); Life Stage and Law [Raifu Suteeji to Hou], Sixth Edition (co-authored, Yuhikaku, 2012); Children and the Law [Kodomo to Hou] (Nihon Kajo Publishing, 2012); Practice and Prospects of Visitation and Child Support [Menkaikouryuu to Youikuhi no Jitsumu to Tenbou] (Nihon Kajo Publishing, 2013), and others.