Tenrei Ōta

Tenrei Ōta (Japanese: Ōta Tenrei), born Takeo Ōta (太田 武夫 Ōta Takeo; 1900–1985) was a Japanese obstetrician-gynaecologist and politician. He invented the Ōta ring, an early intrauterine device (IUD). Throughout his life, he was an outspoken advocate for contraception, abortion, and euthanasia. Some of his beliefs were rooted in eugenics, and during his time as a member of Japan's House of Representatives, he drafted and co-sponsored the Eugenic Protection Law.

Early life and education Takeo Ōta was born in 1900 to a physician's family in the Migochi village of the Kyoto Prefecture in Japan. In 1925, he earned his doctorate from Kyushu University. He then specialised in gynaecology at Kyoto University. He studied human cancer cells to obtain his Ph.D. from Kyoto University, but was denied his degree in 1934 due to his "leftist inclinations". After Japan was defeated in World War II, he was awarded the degree.

Career Ōta began studying contraceptive methods in 1927. Few of his fellow scientists and doctors were interested in the topic, deeming it indecent. He began by studying existing methods, focusing both on barrier contraceptives such as sponges and stem pessaries as well as on early attempts at intrauterine devices to prevent implantation of a fertilised egg. Ōta invented a modified version, which he tested on relatives and acquaintances. First he tried combining multiple gold balls with the ring-shaped device, which he modified by adding spokes that joined in the middle. Later, he modified his design to use one central gold disc, which was attached by spokes to the outer ring. His early versions were made from silver or gold. He also experimented with a plastic version, possibly making him the first to invent a plastic IUD, but he only had access to poor-quality plastics that he ultimately determined were unsuitable. Around the time of the Second Sino-Japanese War, the government officially adopted stricter population planning policies, using the slogan ume yo fuyase yo , and banned artificial contraception methods and abortion in 1941. Due to postwar rationing of silver and gold, he began trialing synthetic materials for his Ōta ring including nylon, vinyl, polyethylene, and combinations thereof. He and two fellow socialists and birth control activists, Shidzue Katō and , introduced the to the House of Representatives in December 1947. Ōta had been the one to choose the name, and coauthored the original version. Ōta is credited with introducing the concept of advance healthcare directives to Japan.

Ōta's proposals generally involved passive euthanasia by withdrawing end-of-life medical care and administering pain relief. He suggested that providing medical care to extend the lives of those who were terminally ill and had expressed a wish to die was in "violation of human dignity".

Ōta's euthanasia advocacy has been criticised by disability rights advocates. Ōta advocated for euthanasia not only in cases where the individual wished to die, but also in the cases of people deemed to be "burdensome" on society. In one of his writings, Ōta suggested, "would it not be ideal if there were fewer [disabled or elderly people]?"