The phrase "a growing question" is correct and usable in written English.
It can be used to refer to a question or issue that is becoming increasingly important or relevant over time.
Example: "As technology advances, climate change has become a growing question for policymakers around the world."
Alternatives: "an emerging question" or "a pressing question".
How much of each is a growing question.
"But there's a growing question in the industry of how many more times can this be repeated.
A growing question out of the NSA leaks, and now the allegation that the FBI wants to get deeper into this game is the definition of metadata, and the simple truth that your metadata might be my content.
A growing question will be to determine whether all the genetic differences revealed by outlier loci are relevant for conservation and species management.
In 2008, then environment minister Phil Woolas, said Britain was rethinking its position on GM due to a "growing question" of whether it could help feed the developing world.
A separate and growing question is how he obtained access to the information in the first place.
The Senate hearing on drone attacks comes at a time of growing questions over whether the policy is in fact counter-productive in fighting al-Qaeda.
A6 NATIONAL A14-18 Bush Vows Firing if an Aide 'Committed a Crime' Faced with growing questions about the role of his close adviser, Karl Rove, in the C.I.A. leak case, President Bush said he would fire any member of his staff who "committed a crime".
Olga V. Kryshtanovskaya, a scholar at the Institute of Sociology of the Russian Academy of Sciences, who has closely studied Mr. Putin's appointees, said Mr. Putin's move appeared to be an answer to the growing questions about the course of democracy in Russia.
The interview, based on what Trump says is a new physical, comes amid growing questions about Hillary Clinton's health, following her abrupt departure from a 9/11 commemoration.
A day later, Hill held an impromptu news conference in an attempt to squelch the growing questions.
