Beate was born in Vienna (Austria) in 1923 as the only daughter of Leo and Augustine Sirota. Her father, Leo, was a talented Russian pianist, sometimes referred to as "the reincarnation of Franz Liszt".

In 1929, at the age of five, Beate and her family left Austria for Japan where her father had been invited to teach at the Tokyo Academy of Music (presently Tokyo University of the Arts) by Kosaku Yamada, one of Japan’s greatest composers.

Beate spent her childhood years at the family’s home in Nogizaka, Tokyo. At the age of 15 (1938), she left for the US to study at Milles College in California. ( ). WWII broke out in 1939.

Soon after World War II ended in 1945 Beate returned to Japan as a member of staff at General Head Quarters (GHQ) in Tokyo. (GHQ was an entity created by the Allied Powers in Japan in 1945 to implement The Potsdam Declaration (, which contained the recommendations to Japan, including its unconditional surrender.)

The then merely twenty-two year old Beate was assigned to the Committee that would be drafting the new democratic Constitution for Japan. Her particular task was to propose human rights articles for inclusion in the Constitution.

Although not all Beate’s drafts were included in the same way as she had drafted, the spirit of her work nevertheless became the basis for the following two articles:
• Article 14 on basic human rights and
• Article 24 on the essential equality of the sexes.

Meanwhile, she also witnessed history in the making as an interpreter for the negotiation process between GHQ and the Japanese Government about what form the new democratic governance structure in Japan should be taking on after WWII.

In 1996, Beate openly addressed the Japanese public for the first time in 1996. Since then she has spoken in public over 200 times on these issues all over Japan.

In 1997 she (Beate) was attributed the Avon-Japan Woman’s Award, that honours women who have empowered and given hope to other women.

In 2005 she was awarded the 9th Ryoko Akamatsu Award.

Beate spoke six languages fluently (English, Japanese, Russian, German, French and Spanish). She lived for the better part of her life in New York City and passed away on 30 December 2012.