age-old question

Translations
вечный вопрос
The age-old question of whether the chicken or the egg came first remains unanswered.
Вечный вопрос о том, что появилось первым, курица или яйцо, остается без ответа.
Definitions
A question that has been asked for a very long time, often reflecting enduring concerns or dilemmas that have persisted throughout history.