A boy in western Japan born through host surrogacy was recently granted the same status as a child born conventionally in the first known case in the country, an obstetrician said Wednesday.

The boy was born in February last year with his biological grandmother in her late 50s serving as the surrogate mother, using the fertilized eggs of her daughter, who has no uterus, and her husband, according to Yahiro Netsu, director of Suwa Maternity Clinic in Shimosuwa, Nagano Prefecture. He declined to disclose where the parents live, saying only that they reside in western Japan.

Babies born through host surrogacy — a controversial practice in Japan — are usually registered as adopted children of their biological parents.

In line with the rule that the woman who has given birth is regarded as the mother of the newborn, the boy was initially registered as the son of the grandmother, but the family filed a petition with a family court for the boy to be granted "special adoption status" as the son of his biological parents.

In family registries, adopted children are declared as such, but those adopted under a special civil code clause are registered no differently from children by birth. Relations with the originally registered parents are legally severed and dissolution of the adoption is banned.

Several families have filed for special permission to register their children born through host surrogacy as their own children, but have had to register them as adopted after courts rejected their requests, Netsu said.

There is no legal prohibition on surrogate births, but the Japan Society of Obstetrics and Gynecology has a guideline banning the practice.