Obituary of Actor Yul Brynner's Only Son

choi

Clay Risen, Rock Brynner, 76, Hollywood Scion Who Paved His Own Path, Is Dead. New York Times, Oct 26, 2023, at page A 22.
https://www.nytimes.com/2023/10/25/books/rock-brynner-dead.html

Note:
(a)
(i) Yul Brynner
https://en.wikipedia.org/wiki/Yul_Brynner
(1920 – 1985 (died of lung cancer; he had smoked); born Yuliy Borisovich Briner)
(ii) Eastern Slavic naming customs
https://en.wikipedia.org/wiki/Eastern_Slavic_naming_customs
(given name, patronymic name, and family name: in that order; section 2 Patronymics)

section 1 Given names, section 1.2 Females: The table contains an item: Russian variant Юлия -- Latin-alphabet transliteration Julija / Yuliya / Yuliia -- equivalent to Julia or Julie.

This, together with
Julius Martov
https://en.wikipedia.org/wiki/Julius_Martov
(born Yuliy Osipovich Tsederbaum)
shows Yuliy is male given name in Russia, equivalent to Julius. See Julian (given name)
https://en.wikipedia.org/wiki/Julian_(given_name)
("The name is based on the Roman [given] name Julianus, which was derived from Julius")

Nothing online shows why Martov picked that name.

(b) The article included a photo
"[credit:] Mitchell Tapper/Associated Press
whose caption was: "The actor Yul Brynner, center, with his son, Rock, and Isaac Tigrett at the opening of Hard Rock Cafe in New York in 1984.